/**
 * @group Web APIs
 */
declare var self: typeof globalThis;

/**
 * @group DOM Events
 */
interface EventMap {
  fetch: FetchEvent;
}

/**
 * @group DOM Events
 */
interface EventListenerMap {
  fetch: FetchEventListener;
}

/**
 * @group DOM Events
 */
interface FetchEventListener {
  (this: typeof globalThis, event: FetchEvent): any;
}
/**
 * @group DOM Events
 */
declare var onfetch: FetchEventListener;

/**
 * This is a fetch specific implementation of [addEventListener](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener), and is very similar to [handling FetchEvent from a Service Worker](https://developer.mozilla.org/en-US/docs/Web/API/FetchEvent/request).
 *
 * For Fastly Compute, this will be the entrypoint in handling your downstream request from your client.
 * @group DOM Events
 */
declare function addEventListener<K extends keyof EventMap>(
  type: K,
  listener: EventListenerMap[K],
): void;

/**
 * @deprecated This has moved to {@link "fastly:backend".BackendConfiguration} - This global variable will be removed in the next major version.
 * @hidden
 */
declare interface BackendConfiguration {
  /**
   * The name of the backend.
   * @deprecated to avoid name collisions it is recommended to use auto-generated names by omitting this property.
   */
  name?: string;
  /**
   * A hostname, IPv4, or IPv6 address for the backend as well as an optional port.
   * E.G. "hostname", "ip address", "hostname:port", or "ip address:port"
   */
  target: string;
  /**
   * If set, will force the HTTP Host header on connections to this backend to be the supplied value.
   */
  hostOverride?: string;
  /**
   * Maximum duration in milliseconds to wait for a connection to this backend to be established.
   * If exceeded, the connection is aborted and a 503 response will be presented instead.
   * Defaults to 1,000 milliseconds.
   */
  connectTimeout?: number;
  /**
   * Maximum duration in milliseconds to wait for the server response to begin after a TCP connection is established and the request has been sent.
   * If exceeded, the connection is aborted and a 503 response will be presented instead.
   * Defaults to 15,000 milliseconds.
   */
  firstByteTimeout?: number;
  /**
   * Maximum duration in milliseconds that Fastly will wait while receiving no data on a download from a backend.
   * If exceeded, the response received so far will be considered complete and the fetch will end.
   * Defaults to 10,000 milliseconds.
   */
  betweenBytesTimeout?: number;
  /**
   * Whether or not to require TLS for connections to this backend.
   */
  useSSL?: boolean;
  /**
   * Minimum allowed TLS version on SSL connections to this backend.
   * If the backend server is not able to negotiate a connection meeting this constraint, a 503 response will be presented instead.
   */
  tlsMinVersion?: number;
  /**
   * Maximum allowed TLS version on SSL connections to this backend.
   * If the backend server is not able to negotiate a connection meeting this constraint, a 503 response will be presented instead.
   */
  tlsMaxVersion?: number;
  /**
   * Define the hostname that the server certificate should declare.
   */
  certificateHostname?: string;
  /**
   * The CA certificate to use when checking the validity of the backend.
   */
  caCertificate?: string;
  /**
   * List of OpenSSL ciphers to support for connections to this origin.
   * If the backend server is not able to negotiate a connection meeting this constraint, a 503 response will be presented instead.
   */
  ciphers?: string;
  /**
   * The SNI hostname to use on connections to this backend.
   */
  sniHostname?: string;
  /**
   * @experimental
   *
   * When enabled, sets that this backend is to be used for gRPC traffic.
   *
   * Warning: When using this experimental feature, no guarantees are provided for behaviours for
   * backends that do not provide gRPC traffic.
   */
  grpc?: boolean;
  /**
   * Set the client certificate to be provided to the server during the initial TLS handshake.
   *
   * @throws {TypeError} Throws a TypeError if the value is not an object of the correct type.
   */
  clientCertificate?: {
    certificate: string;
    key: import('fastly:secret-store').SecretStoreEntry;
  };

  /**
   * Enables and sets the HTTP keepalive time in milliseconds for the backend.
   */
  httpKeepalive?: number;

  /**
   * Enables and sets the TCP keep alive options for the backend.
   * Setting to boolean true enables keepalive with the default options.
   */
  tcpKeepalive?:
    | boolean
    | {
        /**
         * Configure how long to wait after the last sent data over the TCP connection before
         * starting to send TCP keepalive probes.
         */
        timeSecs?: number;

        /**
         * Configure how long to wait between each TCP keepalive probe sent to the backend to determine if it is still active.
         */
        intervalSecs?: number;

        /**
         * Number of probes to send to the backend before it is considered dead.
         */
        probes?: number;
      };
}

/**
* Class for creating new [Fastly Backends](https://developer.fastly.com/reference/api/services/backend/).
*
* **Note**: Can only be used when processing requests, not during build-time initialization.
* @deprecated This has moved to {@link "fastly:backend".Backend} - This global variable will be removed in the next major version.
@hidden
*/
declare class Backend {
  /**
   * Creates a new Backend instance
   *
   * @example
   * Construct a new backend with all properties set to their default values:
   * ```js
   * const myBackend = new Backend({ name: 'fastly', target: 'www.fastly.com'});
   * ```
   */
  constructor(configuration: BackendConfiguration);

  /**
   * The name of the backend
   */
  readonly name: string;

  /**
   * Whether this backend was dynamically created by the running service.
   */
  readonly isDynamic: boolean;
  /**
   * The host target for the backend
   */
  readonly target: string;
  /**
   * The host header override defined for the backend.
   *
   * See https://docs.fastly.com/en/guides/specifying-an-override-host for more information.
   */
  readonly hostOverride: string;
  /**
   * The backend port
   */
  readonly port: number;
  /**
   * The connect timeout for the backend in milliseconds, if available.
   */
  readonly connectTimeout: number | null;
  /**
   * The first byte timeout for the backend in milliseconds, if available.
   */
  readonly firstByteTimeout: number | null;
  /**
   * The between bytes timeout for the backend in milliseconds, if available.
   */
  readonly betweenBytesTimeout: number | null;
  /**
   * The HTTP keepalive time for the backend in milliseconds.
   */
  readonly httpKeepaliveTime: number;
  /**
   * The TCP keepalive configuration, if TCP keepalive is enabled.
   */
  readonly tcpKeepalive: null | {
    /**
     * The keepalive time in seconds.
     */
    timeSecs: number;
    /**
     * The interval in seconds between probes.
     */
    intervalSecs: number;
    /**
     * The number of probes to send before terminating the keepalive.
     */
    probes: number;
  };
  /**
   * Whether the backend is configured to use SSL.
   */
  readonly isSSL: boolean;
  /**
   * The minimum SSL version number this backend will use, if available.
   */
  readonly tlsMinVersion: 1 | 1.1 | 1.2 | 1.3 | null;
  /**
   * The maximum SSL version number this backend will use, if available.
   */
  readonly tlsMaxversion: 1 | 1.1 | 1.2 | 1.3 | null;

  /**
   * Get the health of this backend.
   */
  health(): 'healthy' | 'unhealthy' | 'unknown';

  /**
   * Returns the name associated with the Backend instance.
   * @deprecated Use `backend.name` instead.
   */
  toName(): string;

  /**
   * Returns the name associated with the Backend instance.
   *
   * @deprecated Use `backend.name` instead.
   */
  toString(): string;

  /**
   * Returns a boolean indicating if a Backend with the given name exists or not.
   */
  static exists(name: string): boolean;

  /**
   * Returns the Backend instance with the given name, if one exists. If one does not exist, an error is thrown.
   */
  static fromName(name: string): Backend;

  /**
   * Returns a string representing the health of the given Backend instance.
   * Possible values are:
   *
   * "healthy" - The backend's health check has succeeded, indicating the backend is working as expected and should receive requests.
   * "unhealthy" - The backend's health check has failed, indicating the backend is not working as expected and should not receive requests.
   * "unknown" - The backend does not have a health check configured.
   *
   * @deprecated Use `backend.health()` ({@link Backend.prototype.health}) instead.
   */
  static health(backend: Backend): 'healthy' | 'unhealthy' | 'unknown';
}

/**
 * A Fastly Compute specific implementation of [FetchEvent](https://developer.mozilla.org/en-US/docs/Web/API/FetchEvent/FetchEvent).
 * @group DOM Events
 */
declare interface FetchEvent {
  /**
   * Information about the downstream client that made the request
   */
  readonly client: ClientInfo;

  /**
   * Information about the server which received the request.
   */
  readonly server: ServerInfo;
  /**
   * The downstream request that came from the client
   */
  readonly request: Request;

  /**
   * Send a response back to the client.
   *
   * **Note**: The service will be kept alive until the response has been fully sent.
   *
   * If the response contains a streaming body created by the service itself, then the service
   * will be kept alive until the body {@link ReadableStream} has been closed or errored.
   *
   * However, if the body is a stream originating in a request to a backend, i.e. if a backend
   * response's {@link Response.body} is passed as input to the {@link Response} constructor, the
   * service will not be kept alive until sending the body has finished.
   *
   * **Note**: If `response` is a `Promise`, the service will be kept alive until the
   * response has been resolved or rejected, and the {@link Response} it resolved to has been
   * fully sent.
   *
   * **Note**: Use {@link FetchEvent.waitUntil} to extend the service's lifetime further if
   * necessary.
   *
   * @param response - Response to send back down to the client
   */
  respondWith(response: Response | PromiseLike<Response>): void;

  /**
   * Extend the service's lifetime to ensure asynchronous operations succeed.
   *
   * By default, a service will shut down as soon as the response passed to
   * {@link FetchEvent.respondWith | respondWith} has been sent. `waitUntil` can be used to
   * ensure that the service will stay alive until additional asynchronous operations have
   * completed, such as sending telemetry data to a separate backend after the response has
   * been sent.
   *
   * @param promise - The `Promise` to wait for
   */
  waitUntil(promise: Promise<any>): void;
}

/**
 * Set the cache override mode on a request
 *
 * None
 *   Do not override the behavior specified in the origin response’s cache control headers.
 * Pass
 *   Do not cache the response to this request, regardless of the origin response’s headers.
 * Override
 *   Override particular cache control settings using a {@linkcode CacheOverride} object.
 *
 * The origin response’s cache control headers will be used for ttl and stale_while_revalidate if None.
 *
 * @deprecated This has moved to {@link "fastly:cache-override".CacheOverrideMode} - This global type will be removed in the next major version.
 * @hidden
 */
declare type CacheOverrideMode = 'none' | 'pass' | 'override';

/**
 * Base class for Cache Override, which is used to configure caching behavior.
 * @deprecated This has moved to {@link "fastly:cache-override".CacheOverrideInit} - This global interface will be removed in the next major version.
 * @hidden
 */
declare interface CacheOverrideInit {
  /**
   * Override the caching behavior of this request to use the given Time to Live (TTL), in seconds.
   */
  ttl?: number;
  /**
   * Override the caching behavior of this request to use the given `stale-while-revalidate` time,
   * in seconds
   */
  swr?: number;
  /**
   * Override the caching behavior of this request to include the given surrogate key, provided as
   * a header value.
   *
   * See the [Fastly surrogate keys guide](https://docs.fastly.com/en/guides/purging-api-cache-with-surrogate-keys)
   * for details.
   */
  surrogateKey?: string;
  /**
   * Override the caching behavior of this request to enable or disable PCI/HIPAA-compliant
   * non-volatile caching.
   *
   * By default, this is false, which means the request may not be PCI/HIPAA-compliant. Set it to
   * true to enable compliant caching.
   *
   * See the [Fastly PCI-Compliant Caching and Delivery documentation](https://docs.fastly.com/products/pci-compliant-caching-and-delivery)
   * for details.
   */
  pci?: boolean;
}

/**
 * Configures the caching behavior of a {@linkcode Response}.
 *
 * Normally, the HTTP Headers on a Response would control how the Response is cached,
 * but CacheOverride can be set on a {@linkcode Request}, to define custom caching behavior.
 *
 * @deprecated This has moved to {@link "fastly:cache-override".CacheOverride} - This global interface will be removed in the next major version.
 * @hidden
 */
declare interface CacheOverride extends CacheOverrideInit {
  mode: CacheOverrideMode;
}

/**
 * @deprecated This has moved to {@link "fastly:cache-override".CacheOverride} - This global variable will be removed in the next major version.
 * @hidden
 */
declare var CacheOverride: {
  prototype: CacheOverride;
  new (mode: CacheOverrideMode, init?: CacheOverrideInit): CacheOverride;
};

/**
 * Information about the downstream client making the request to the Fastly Compute service.
 */
declare interface ClientInfo {
  /**
   * A string representation of the IPv4 or IPv6 address of the downstream client.
   *
   * While always defined on Fastly compute, on environments where these fields are unavailable,
   * such as Viceroy, these fields may return *null*.
   */
  readonly address: string;
  readonly geo: import('fastly:geolocation').Geolocation | null;
  readonly tlsJA3MD5: string | null;
  readonly tlsCipherOpensslName: string | null;
  readonly tlsProtocol: string | null;
  readonly tlsClientCertificate: ArrayBuffer | null;
  readonly tlsClientHello: ArrayBuffer | null;
}

/**
 * Information about the server receiving the request for the Fastly Compute service.
 */
declare interface ServerInfo {
  /**
   * A string representation of the IPv4 or IPv6 address of the server which received the request.
   */
  readonly address: string;
}

/**
 * Class for accessing [Fastly Edge Dictionaries](https://docs.fastly.com/en/guides/about-edge-dictionaries).
 *
 * **Note**: Can only be used when processing requests, not during build-time initialization.
 *
 * @deprecated This has moved to {@link "fastly:config-store".ConfigStore} - This global class will be removed in the next major version.
 * @hidden
 */
declare class ConfigStore {
  /**
   * Creates a new ConfigStore object
   */
  constructor(name: string);
  /**
   * Get a value for a key in the config-store.
   */
  get(key: string): string;
}

/**
 * Class for accessing [Fastly Edge Dictionaries](https://docs.fastly.com/en/guides/about-edge-dictionaries).
 *
 * **Note**: Can only be used when processing requests, not during build-time initialization.
 * @deprecated This has moved to {@link "fastly:dictionary".Dictionary} - This global class will be removed in the next major version.
 * @hidden
 */
declare class Dictionary {
  /**
   * Creates a new Dictionary object, and opens an edge dictionary to query
   */
  constructor(name: string);
  /**
   * Get a value for a key in the dictionary
   */
  get(key: string): string;
}

/**
 * [Fastly Geolocation](https://developer.fastly.com/reference/vcl/variables/geolocation/)
 * information about an IP address
 *
 * Can be retrieved for the incoming request's client IP address using the
 * {@linkcode ClientInfo#geo} accessor, and for arbitrary addresses using
 * {@linkcode Fastly.getGeolocationForIpAddress}.
 * @deprecated This has moved to {@link "fastly:geolocation".Geolocation} - This global interface will be removed in the next major version.
 * @hidden
 */
declare interface Geolocation {
  /**
   * The name of the organization associated with as_number.
   *
   * For example, fastly is the value given for IP addresses under AS-54113.
   */
  as_name: string | null;

  /**
   * [Autonomous system](https://en.wikipedia.org/wiki/Autonomous_system_(Internet)) (AS) number.
   */
  as_number: number | null;

  /**
   * The telephone area code associated with an IP address.
   *
   * These are only available for IP addresses in the United States, its territories, and Canada.
   */
  area_code: number | null;

  /**
   * City or town name.
   */
  city: string | null;

  /**
   * Connection speed.
   */
  conn_speed: string | null;

  /**
   * Connection type.
   */
  conn_type: string | null;

  /**
   * Continent.
   */
  continent: string | null;

  /**
   * A two-character [ISO 3166-1](https://en.wikipedia.org/wiki/ISO_3166-1) country code for the country associated with an IP address.
   *
   * The US country code is returned for IP addresses associated with overseas United States military bases.
   *
   * These values include subdivisions that are assigned their own country codes in ISO 3166-1. For example, subdivisions NO-21 and NO-22 are presented with the country code SJ for Svalbard and the Jan Mayen Islands.
   */
  country_code: string | null;

  /**
   * A three-character [ISO 3166-1 alpha-3](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-3) country code for the country associated with the IP address.
   *
   * The USA country code is returned for IP addresses associated with overseas United States military bases.
   */
  country_code3: string | null;

  /**
   * Country name.
   *
   * This field is the [ISO 3166-1](https://en.wikipedia.org/wiki/ISO_3166-1) English short name for a country.
   */
  country_name: string | null;

  /**
   * Time zone offset from Greenwich Mean Time (GMT) for `city`.
   */
  gmt_offset: string | null;

  /**
   * Latitude, in units of degrees from the equator.
   *
   * Values range from -90.0 to +90.0 inclusive, and are based on the [WGS 84](https://en.wikipedia.org/wiki/World_Geodetic_System) coordinate reference system.
   */
  latitude: number | null;

  /**
   * Longitude, in units of degrees from the [IERS Reference Meridian](https://en.wikipedia.org/wiki/IERS_Reference_Meridian).
   *
   * Values range from -180.0 to +180.0 inclusive, and are based on the [WGS 84](https://en.wikipedia.org/wiki/World_Geodetic_System) coordinate reference system.
   */
  longitude: number | null;

  /**
   * Metro code, representing designated market areas (DMAs) in the United States.
   */
  metro_code: number | null;

  /**
   * The postal code associated with the IP address.
   *
   * These are available for some IP addresses in Australia, Canada, France, Germany, Italy, Spain, Switzerland, the United Kingdom, and the United States.
   *
   * For Canadian postal codes, this is the first 3 characters. For the United Kingdom, this is the first 2-4 characters (outward code). For countries with alphanumeric postal codes, this field is a lowercase transliteration.
   */
  postal_code: string | null;

  /**
   * Client proxy description.
   */
  proxy_description: string | null;

  /**
   * Client proxy type.
   */
  proxy_type: string | null;

  /**
   * [ISO 3166-2](https://en.wikipedia.org/wiki/ISO_3166-2) country subdivision code.
   *
   * For countries with multiple levels of subdivision (for example, nations within the United Kingdom), this variable gives the more specific subdivision.
   *
   * This field can be None for countries that do not have ISO country subdivision codes. For example, None is given for IP addresses assigned to the Åland Islands (country code AX, illustrated below).
   */
  region: string | null;

  /**
   * Time zone offset from coordinated universal time (UTC) for `city`.
   */
  utc_offset: number | null;
}

/**
 * Class for accessing a [Fastly KV Store](https://developer.fastly.com/reference/api/kv-store/).
 *
 * A KV Store is a persistent, globally consistent key-value store.
 *
 * **Note**: Can only be used when processing requests, not during build-time initialization.
 * @deprecated This has moved to {@link "fastly:kv-store".KVStore} - This global class will be removed in the next major version.
 * @hidden
 */
declare class KVStore {
  /**
   * Creates a new JavaScript KVStore object which interacts with the Fastly KV Store named `name`.
   *
   * @param name Name of the Fastly KV Store to interact with. A name cannot be empty, contain Control characters, or be longer than 255 characters.
   */
  constructor(name: string);
  /**
   * Gets the value associated with the key `key` in the KV Store.
   * When the key is present, a resolved Promise containing an KVStoreEntry will be returned which contains the associated value.
   * When the key is absent, a resolved Promise containing null is returned.
   * @param key The key to retrieve from within the KV Store. A key cannot:
   * - Be any of the strings "", ".", or ".."
   * - Start with the string ".well-known/acme-challenge/""
   * - Contain any of the characters "#;?^|\n\r"
   * - Be longer than 1024 characters
   */
  get(key: string): Promise<KVStoreEntry | null>;

  /**
   * Write the value of `value` into the KV Store under the key `key`.
   *
   * Note: KV Store is eventually consistent, this means that the updated contents associated with the key `key` may not be available to read from all
   * edge locations immediately and some edge locations may continue returning the previous contents associated with the key.
   *
   * @param key The key to associate with the value. A key cannot:
   * - Be any of the strings "", ".", or ".."
   * - Start with the string ".well-known/acme-challenge/""
   * - Contain any of the characters "#;?^|\n\r"
   * - Be longer than 1024 characters
   * @param value The value to store within the KV Store.
   */
  put(key: string, value: BodyInit): Promise<undefined>;
}

/**
 * Class for interacting with a [Fastly KV Store](https://developer.fastly.com/reference/api/kv-store/) entry.
 *
 * @deprecated This has moved to {@link "fastly:kv-store".KVStoreEntry} - This global interface will be removed in the next major version.
 * @hidden
 */
declare interface KVStoreEntry {
  /**
   * A ReadableStream with the contents of the entry.
   */
  get body(): ReadableStream;
  /**
   * A boolean value that indicates whether the body has been read from already.
   */
  get bodyUsed(): boolean;
  /**
   * Reads the body and returns it as a promise that resolves with a string.
   * The response is always decoded using UTF-8.
   */
  text(): Promise<string>;
  /**
   * Reads the body and returns it as a promise that resolves with the result of parsing the body text as JSON.
   */
  json(): Promise<object>;
  /**
   * Reads the body and returns it as a promise that resolves with an ArrayBuffer.
   */
  arrayBuffer(): Promise<ArrayBuffer>;
  // And eventually formData and blob once we support them on Request and Response, too.
}

/**
 * The URL class as [specified by WHATWG](https://url.spec.whatwg.org/#url-class)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/URL | URL on MDN}
 * @group Web APIs
 */
declare class URL {
  constructor(url: string, base?: string | URL);

  get href(): string;
  set href(V: string);

  get origin(): string;

  get protocol(): string;
  set protocol(V: string);

  get username(): string;
  set username(V: string);

  get password(): string;
  set password(V: string);

  get host(): string;
  set host(V: string);

  get hostname(): string;
  set hostname(V: string);

  get port(): string;
  set port(V: string);

  get pathname(): string;
  set pathname(V: string);

  get search(): string;
  set search(V: string);

  get searchParams(): URLSearchParams;

  get hash(): string;
  set hash(V: string);

  toJSON(): string;

  readonly [Symbol.toStringTag]: 'URL';
}

/**
 * The URLSearchParams class as [specified by WHATWG](https://url.spec.whatwg.org/#interface-urlsearchparams)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams | URLSearchParams on MDN}
 * @group Web APIs
 */
declare class URLSearchParams {
  constructor(
    init?:
      | ReadonlyArray<readonly [name: string, value: string]>
      | Iterable<readonly [name: string, value: string]>
      | { readonly [name: string]: string }
      | string,
  );

  append(name: string, value: string): void;
  delete(name: string): void;
  get(name: string): string | null;
  getAll(name: string): string[];
  has(name: string): boolean;
  set(name: string, value: string): void;
  sort(): void;

  keys(): IterableIterator<string>;
  values(): IterableIterator<string>;
  entries(): IterableIterator<[name: string, value: string]>;
  forEach<THIS_ARG = void>(
    callback: (
      this: THIS_ARG,
      value: string,
      name: string,
      searchParams: this,
    ) => void,
    thisArg?: THIS_ARG,
  ): void;

  readonly [Symbol.toStringTag]: 'URLSearchParams';
  [Symbol.iterator](): IterableIterator<[name: string, value: string]>;
}

/**
 * Interface for logging to stdout for
 * [live log monitoring](https://developer.fastly.com/learning/compute/testing/#live-log-monitoring-in-your-console).
 *
 * **Note**: This implementation accepts any number of arguments. String representations of each object are appended
 * together in the order listed and output. Unlike the `Console` built-in in browsers and Node.js, this implementation
 * does not perform string substitution.
 *
 * **Note**: Messages are prefixed with the respective log level, starting with an upper-case letter, e.g. `"Log: "`.
 * @group Console API
 */
interface Console {
  assert(condition?: boolean, ...data: any[]): void;
  clear(): void;
  count(label?: string): void;
  countReset(label?: string): void;
  debug(...data: any[]): void;
  dir(item?: any, options?: any): void;
  dirxml(...data: any[]): void;
  error(...data: any[]): void;
  group(...data: any[]): void;
  groupCollapsed(...data: any[]): void;
  groupEnd(): void;
  info(...data: any[]): void;
  log(...data: any[]): void;
  table(tabularData?: any, properties?: string[]): void;
  time(label?: string): void;
  timeEnd(label?: string): void;
  timeLog(label?: string, ...data: any[]): void;
  trace(...data: any[]): void;
  warn(...data: any[]): void;
}

/**
 * The global {@linkcode Console} instance
 * @group Console API
 */
declare var console: Console;

/**
 * An implementation of the [WHATWG Encoding Standard](https://encoding.spec.whatwg.org/) `TextEncoder` API. All
 * instances of `TextEncoder` only support UTF-8 encoding.
 *
 * TextEncoder takes a stream of code points as input and emits a stream of UTF-8 bytes.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/TextEncoder | TextEncoder on MDN}
 * @example
 * ```js
 * const encoder = new TextEncoder();
 * const uint8array = encoder.encode('a string to encode');
 * ```
 * @group Encoding API
 */
declare class TextEncoder {
  /**
   * Returns a newly constructed TextEncoder that will generate a byte stream with UTF-8 encoding.
   */
  constructor();
  /**
   * The TextEncoder.encoding read-only property returns a string containing the name of the encoding algorithm used by the specific encoder.
   * It is always set to the value "utf-8".
   */
  readonly encoding: 'utf-8';
  /**
   * UTF-8 encodes the `input` string and returns a `Uint8Array` containing the encoded bytes.
   * @param [input='an empty string'] The text to encode.
   */
  encode(input?: string): Uint8Array;
  // /**
  //  * UTF-8 encodes the `src` string to the `dest` Uint8Array and returns an object
  //  * containing the read Unicode code units and written UTF-8 bytes.
  //  *
  //  * ```js
  //  * const encoder = new TextEncoder();
  //  * const src = 'this is some data';
  //  * const dest = new Uint8Array(10);
  //  * const { read, written } = encoder.encodeInto(src, dest);
  //  * ```
  //  * @param src The text to encode.
  //  * @param dest The array to hold the encode result.
  //  */
  // encodeInto(src: string, dest: Uint8Array): TextEncoderEncodeIntoResult;
}

// https://encoding.spec.whatwg.org/#dictdef-textencoderencodeintoresult
// declare interface TextEncoderEncodeIntoResult {
//   read: number;
//   written: number;
// }

/**
 * TextDecoder takes a stream UTF-8 bytes as input and emits a stream of code points
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/TextDecoder | TextDecoder on MDN}
 *
 * **Note**: On Fastly Compute, TextDecoder only supports UTF-8 bytes as input, and always operates
 * in non-fatal mode.
 * @group Encoding API
 */
declare class TextDecoder {
  // TODO: We should throw a RangeError if supplied a `label` that we do not support
  constructor(label?: 'unicode-1-1-utf-8' | 'utf-8' | 'utf8');
  decode(input?: ArrayBuffer | ArrayBufferView): string;
  get encoding(): 'utf-8';
}

/**
 * Simple interface for logging to
 * [third party logging providers](https://developer.fastly.com/learning/integrations/logging)
 *
 * Instances of Logger for specific endpoints can be created using {@linkcode Fastly.getLogger}.
 * @deprecated This has moved to {@link "fastly:logger".Logger} - This global class will be removed in the next major version.
 * @hidden
 */
declare interface Logger {
  /**
   * Send the given message, converted to a string, to this Logger instance's endpoint
   */
  log(message: any): void;
}

/**
 * Fastly-specific APIs available to Fastly Compute JS services
 * @deprecated
 * @hidden
 */
declare interface Fastly {
  /**
   * @deprecated This has moved to {@link "fastly:experimental".setBaseURL} - This will be removed in the next major version.
   * @hidden
   * @experimental
   */
  set baseURL(base: URL | null | undefined);
  /**
   * @deprecated This will be removed in the next major version.
   * @hidden
   * @experimental
   */
  get baseURL(): URL | null;
  /**
   * @deprecated This has moved to {@link "fastly:experimental".setDefaultBackend} - This will be removed in the next major version.
   * @hidden
   * @experimental
   */
  set defaultBackend(backend: string);
  /**
   * @deprecated This will be removed in the next major version.
   * @hidden
   * @experimental
   */
  get defaultBackend(): string;
  /**
   * Property to access the environment variables for the Fastly Compute service.
   * @hidden
   * @experimental
   */
  env: {
    /**
     * Function to get the environment variable value, for the provided environment variable name.
     *
     * For additional references, see the [Fastly Developer Hub for Compute Environment Variables](https://developer.fastly.com/reference/compute/ecp-env/)
     *
     * @param name The name of the environment variable
     * @returns the value of the environemnt variable
     * @deprecated This has moved to {@link "fastly:env".env} - This function will be removed in the next major version.
     * @hidden
     */
    get(name: string): string;
  };

  /**
   * JavaScript SDK version string for the JS runtime build.
   * @hidden
   */
  sdkVersion: string;

  /**
   * Creates a new {@linkcode Logger} instance for the given
   * [named log endpoint](https://developer.fastly.com/learning/integrations/logging).
   *
   * **Note**: Can only be used when processing requests, not during build-time initialization.
   * @deprecated This function will be removed in the next major version. Use of this function can be replaced with the fastly logger class {@link "fastly:logger".Logger}
   * @hidden
   */
  getLogger(endpoint: string): Logger;

  /**
   * Causes the Fastly Compute JS runtime environment to log debug information to stdout.
   *
   * **Note**: This is mostly for internal debugging purposes and will generate highly unstable
   * output.
   *
   * @deprecated This has moved to {@link "fastly:experimental".enableDebugLogging} - This function will be removed in the next major version.
   * @hidden
   * @experimental
   */
  enableDebugLogging(enabled: boolean): void;

  /**
   * Retrieve geolocation information about the given IP address.
   *
   * @param address - the IPv4 or IPv6 address to query
   *
   * **Note**: Can only be used when processing requests, not during build-time initialization.
   * @deprecated This has moved to {@link "fastly:geolocation".getGeolocationForIpAddress} - This function will be removed in the next major version.
   * @hidden
   */
  getGeolocationForIpAddress(
    address: string,
  ): import('fastly:geolocation').Geolocation;

  /**
   * Embed a file as a Uint8Array.
   *
   * @param path - The path to include, relative to the project's top-level directory
   *
   * **Note**: Can only be used during build-time initialization, not when processing requests.
   *
   * @deprecated This has moved to {@link "fastly:experimental".includeBytes} - This function will be removed in the next major version.
   * @hidden
   * @experimental
   */
  includeBytes(path: string): Uint8Array;
}

/**
 * The global instance of the {@linkcode Fastly} builtin
 * @deprecated
 * @hidden
 */
declare var fastly: Fastly;

/**
 * An API for compressing a stream of data.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/CompressionStream | CompressionStream on MDN}
 *
 * @example
 * In this example a request is made to httpbin.org/html and the response body is compressed using gzip compression.
 *
 * View this example on [Fiddle](https://fiddle.fastly.dev/fiddle/c1326776).
 *
 * ```js
 * async function app(event) {
 *  const req = event.request;
 *  const backendResponse = await fetch("https://httpbin.org/html", { backend: "origin_0" });
 *  if (!backendResponse.body) {
 *    return backendResponse;
 *  }
 *  let resp = new Response(backendResponse.body.pipeThrough(new CompressionStream("gzip")), backendResponse);
 *  resp.headers.set("Content-Encoding", "gzip");
 *  return resp;
 * }
 * addEventListener("fetch", event => event.respondWith(app(event)));
 * ```
 *
 * @group Compression Streams APIs
 */
declare class CompressionStream {
  /**
   * Creates a new `CompressionStream` object which compresses a stream of data.
   *
   * @param format The compression format to use.
   *
   * @throws Throws a `TypeError` if the format passed to the constructor is not supported.
   * @example
   * ```js
   * const gzip = new CompressionStream("gzip");
   * ```
   */
  constructor(format: 'deflate' | 'deflate-raw' | 'gzip');

  /**
   * @example
   * ```js
   * let stream = new CompressionStream("gzip");
   * console.log(stream.readable instanceof ReadableStream); // true
   * ```
   */
  readonly readable: ReadableStream<Uint8Array>;
  /**
   * @example
   * ```js
   * let stream = new CompressionStream("gzip");
   * console.log(stream.writable instanceof WritableStream); // true
   * ```
   */
  readonly writable: WritableStream<Uint8Array>;
}

/**
 * An API for decompressing a stream of data.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/DecompressionStream | DecompressionStream on MDN}
 *
 * @example
 * In this example a request is made to httpbin.org/gzip and the response body is decompressed using gzip decompression.
 *
 * View this example on [Fiddle](https://fiddle.fastly.dev/fiddle/637add51).
 *
 * ```js
 * async function app(event) {
 *  const backendResponse = await fetch("https://httpbin.org/gzip", { backend: "origin_0" });
 *  let resp = new Response(backendResponse.body.pipeThrough(new DecompressionStream("gzip")), backendResponse);
 *  resp.headers.delete('content-encoding');
 *  return resp;
 * }
 * addEventListener("fetch", event => event.respondWith(app(event)));
 * ```
 *
 * @group Compression Streams APIs
 */
declare class DecompressionStream {
  /**
   * Creates a new `DecompressionStream` object which decompresses a stream of
   * data.
   *
   * @param format The compression format to use.
   *
   * @throws Throws a `TypeError` if the format passed to the constructor is not supported.
   * @example
   * ```js
   * const gzip = new DecompressionStream("gzip");
   * ```
   */
  constructor(format: 'deflate' | 'deflate-raw' | 'gzip');

  /**
   * @example
   * ```js
   * let stream = new DecompressionStream("gzip");
   * console.log(stream.readable instanceof ReadableStream); // true
   * ```
   */
  readonly readable: ReadableStream<Uint8Array>;
  /**
   * @example
   * ```js
   * let stream = new DecompressionStream("gzip");
   * console.log(stream.writable instanceof WritableStream); // true
   * ```
   */
  readonly writable: WritableStream<Uint8Array>;
}

// Note: the contents below here are, partially modified, copies of content from TypeScript's
// `lib.dom.d.ts` file.
// We used to keep them in a separate file, referenced using a `/// reference path="..."`
// directive, but that causes the defined types to be absent from TypeDoc output.

/*! *****************************************************************************
Copyright (c) Microsoft Corporation. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use
this file except in compliance with the License. You may obtain a copy of the
License at http://www.apache.org/licenses/LICENSE-2.0

THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
MERCHANTABLITY OR NON-INFRINGEMENT.

See the Apache Version 2.0 License for specific language governing permissions
and limitations under the License.
***************************************************************************** */

/*!
 * This file is largely a subset of TypeScript's lib.dom.d.ts file, with some
 * Fastly Compute-specific additions and modifications. Those modifications are
 * Copyright (c) Fastly Corporation, under the same license as the rest of the file.
 */

/**
 * Used within the
 * [Request](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request) and
 * [Response](https://developer.mozilla.org/en-US/docs/Web/API/Response/Response) constructors.
 * ({@linkcode Request}, and {@linkcode Response})
 * @group Fetch API
 */
declare type BodyInit =
  | ReadableStream
  | ArrayBufferView
  | ArrayBuffer
  | URLSearchParams
  | string;

/**
 * Body for Fetch HTTP Requests and Responses
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Body | Body on MDN}
 * @group Fetch API
 */
declare interface Body {
  readonly body: ReadableStream<Uint8Array> | null;
  readonly bodyUsed: boolean;
  arrayBuffer(): Promise<ArrayBuffer>;
  // blob(): Promise<Blob>;
  // formData(): Promise<FormData>;
  json(): Promise<any>;
  text(): Promise<string>;
}

/**
 * Constructor parameter for
 * [Request](https://developer.mozilla.org/en-US/docs/Web/API/Request)
 *
 * Usually this a URL to the resource you are requesting.
 * @group Fetch API
 */
declare type RequestInfo = Request | string;

/**
 * Constructor parameter for
 * [Request](https://developer.mozilla.org/en-US/docs/Web/API/Request)
 *
 * This contains information to send along with the request (Headers, body, etc...), as well as
 * Fastly specific information.
 * @group Fetch API
 */
declare interface RequestInit {
  /** A BodyInit object or null to set request's body. */
  body?: BodyInit | null;
  // /** A string indicating how the request will interact with the browser's cache to set request's cache. */
  // cache?: RequestCache;
  // /** A string indicating whether credentials will be sent with the request always, never, or only when sent to a same-origin URL. Sets request's credentials. */
  // credentials?: RequestCredentials;
  /** A Headers object, an object literal, or an array of two-item arrays to set request's headers. */
  headers?: HeadersInit;
  // /** A cryptographic hash of the resource to be fetched by request. Sets request's integrity. */
  // integrity?: string;
  // /** A boolean to set request's keepalive. */
  // keepalive?: boolean;
  /** A string to set request's method. */
  method?: string;
  // /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
  // mode?: RequestMode;
  // /** A string indicating whether request follows redirects, results in an error upon encountering a redirect, or returns the redirect (in an opaque fashion). Sets request's redirect. */
  // redirect?: RequestRedirect;
  // /** A string whose value is a same-origin URL, "about:client", or the empty string, to set request's referrer. */
  // referrer?: string;
  // /** A referrer policy to set request's referrerPolicy. */
  // referrerPolicy?: ReferrerPolicy;
  // /** An AbortSignal to set request's signal. */
  // signal?: AbortSignal | null;
  // /** Can only be null. Used to disassociate request from any Window. */
  // window?: null;

  /** The Fastly configured backend name or instance the request should be sent to. */
  backend?: string | import('fastly:backend').Backend;
  cacheOverride?:
    | import('fastly:cache-override').CacheOverride
    | import('fastly:cache-override').ICacheOverride
    | Exclude<import('fastly:cache-override').CacheOverrideMode, 'override'>;
  cacheKey?: string;
  fastly?: {
    decompressGzip?: boolean;
  };
  manualFramingHeaders?: boolean;
}

/**
 * The Request class as [specified by WHATWG](https://fetch.spec.whatwg.org/#ref-for-dom-request%E2%91%A0)
 *
 * **Note**: Can only be used when processing requests, not during build-time initialization.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/Request | Request on MDN}
 * @group Fetch API
 */
interface Request extends Body {
  // /** Returns the cache mode associated with request, which is a string indicating how the request will interact with the browser's cache when fetching. */
  // readonly cache: RequestCache;
  // /** Returns the credentials mode associated with request, which is a string indicating whether credentials will be sent with the request always, never, or only when sent to a same-origin URL. */
  // readonly credentials: RequestCredentials;
  // /** Returns the kind of resource requested by request, e.g., "document" or "script". */
  // readonly destination: RequestDestination;
  /** Returns a Headers object consisting of the headers associated with request. */
  readonly headers: Headers;
  // /** Returns request's subresource integrity metadata, which is a cryptographic hash of the resource being fetched. Its value consists of multiple hashes separated by whitespace. [SRI] */
  // readonly integrity: string;
  // /** Returns a boolean indicating whether or not request can outlive the global in which it was created. */
  // readonly keepalive: boolean;
  /** Returns request's HTTP method, which is "GET" by default. */
  readonly method: string;
  // /** Returns the mode associated with request, which is a string indicating whether the request will use CORS, or will be restricted to same-origin URLs. */
  // readonly mode: RequestMode;
  // /** Returns the redirect mode associated with request, which is a string indicating how redirects for the request will be handled during fetching. A request will follow redirects by default. */
  // readonly redirect: RequestRedirect;
  // /** Returns the referrer of request. Its value can be a same-origin URL if explicitly set in init, the empty string to indicate no referrer, and "about:client" when defaulting to the global's default. This is used during fetching to determine the value of the `Referer` header of the request being made. */
  // readonly referrer: string;
  // /** Returns the referrer policy associated with request. This is used during fetching to compute the value of the request's referrer. */
  // readonly referrerPolicy: ReferrerPolicy;
  // /** Returns the signal associated with request, which is an AbortSignal object indicating whether or not request has been aborted, and its abort event handler. */
  // readonly signal: AbortSignal;
  /** Returns the URL of request as a string. */
  readonly url: string;

  /** Creates a copy of the current Request object. */
  clone(): Request;

  /**
   * The request backend, null for the downstream request itself
   */
  readonly backend: import('fastly:backend').Backend | undefined;
  setCacheOverride(
    override: import('fastly:cache-override').CacheOverride,
  ): void;
  setCacheKey(key: string): void;
  setManualFramingHeaders(manual: boolean): void;

  /**
   * Fastly-specific property - determines whether a request is cacheable per conservative RFC 9111 semantics.
   * In particular, this function checks whether the request method is `GET` or `HEAD`, and
   * considers requests with other methods uncacheable. Applications where it is safe to cache
   * responses to other methods should consider using their own cacheability check instead of
   * this function.
   *
   * This function always returns undefined on hosts not supporting the HTTP Cache API (i.e. Viceroy)
   */
  readonly isCacheable: boolean | undefined;
}

/**
 * @group Fetch API
 */
declare var Request: {
  prototype: Request;
  new (input: RequestInfo | URL, init?: RequestInit): Request;
};

/**
 * Constructor parameter for the [Fetch API Response](https://developer.mozilla.org/en-US/docs/Web/API/Response)
 * This contains information to send along with the response.
 * @group Fetch API
 */
declare interface ResponseInit {
  headers?: HeadersInit;
  status?: number;
  statusText?: string;
  manualFramingHeaders?: boolean;
}

/**
 * The Response class as [specified by WHATWG](https://fetch.spec.whatwg.org/#ref-for-dom-response%E2%91%A0)
 *
 * **Note**: Can only be used when processing requests, not during build-time initialization.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/Response | Response on MDN}
 * @group Fetch API
 */
interface Response extends Body {
  /**
   * The response headers.
   *
   * May be modified event for upstream responses prior to storage in the cache.
   */
  readonly headers: Headers;
  readonly ok: boolean;
  // readonly redirected: boolean;
  /**
   * The response status. May be modified prior to storage in the cache.
   */
  status: number;
  readonly statusText: string;
  // readonly type: ResponseType;
  readonly url: string;
  /**
   * Fastly-specific property - obtain the IP address used for the request
   *
   * Undefined for user-created responses and when the response is returned from the cache.
   * Set cacheOverride: new CacheOverride("pass") to ensure a value.
   */
  readonly ip: string | undefined;
  /**
   * Fastly-specific property - Obtain the port used for the request
   *
   * Undefined for user-created responses and when the response is returned from the cache.
   * Set cacheOverride: new CacheOverride("pass") to ensure a value.
   */
  readonly port: number | undefined;
  // clone(): Response;
  setManualFramingHeaders(manual: boolean): void;
  /**
   * The response backend, if an upstream response
   */
  readonly backend: import('fastly:backend').Backend | undefined;
  /**
   * Fastly-specific property - Returns whether the `Response` resulted from a cache hit.
   * For request collapsing, typically one response will show as a miss, and the others
   * (that awaited that response) will show as hits.
   *
   * Undefined if the environment does not support the new HTTP Cache hostcalls.
   */
  readonly cached: boolean | undefined;
  /**
   * Fastly-specific property - Returns whether the cached `Response` is considered stale.
   *
   * Undefined if the environment does not support the new HTTP Cache hostcalls.
   */
  readonly stale: boolean | undefined;
  /**
   * Fastly-specific property - Get the Time to Live (TTL) in the cache for this response in seconds, if it is cached.
   *
   * The TTL determines the duration of "freshness" for the cached response
   * after it is inserted into the cache.
   *
   * Undefined if the response is not cached or the environment does not support the HTTP Cache hostcalls. May be modified prior to injection into the cache.
   */
  ttl: number | undefined;
  /**
   * Fastly-specific property - The current age of the response in seconds, if it is cached.
   *
   * Undefined if the response is not cached or the environment does not support the HTTP Cache hostcalls. May be modified prior to injection into the cache.
   */
  readonly age: number | undefined;
  /**
   * Fastly-specific property - The time in seconds for which the response can safely be used despite being considered stale, if it is cached.
   *
   * Undefined if the response is not cached or the environment does not support the HTTP Cache hostcalls. May be modified prior to injection into the cache.
   */
  swr: number | undefined;
  /**
   * Fastly-specific property - The set of request headers for which the response may vary.
   *
   * Undefined if the response is not cached or the environment does not support the HTTP Cache hostcalls. May be modified prior to injection into the cache.
   */
  vary: Array<string> | undefined;
  /**
   * Fastly-specific property - The surrogate keys for the cached response.
   *
   * Undefined if the response is not cached or the environment does not support the HTTP Cache hostcalls. May be modified prior to injection into the cache.
   */
  surrogateKeys: Array<string> | undefined;
  /**
   * Fastly-specific property - Get or set whether this response should only be stored via PCI/HIPAA-compliant non-volatile caching.
   *
   * See the [Fastly PCI-Compliant Caching and Delivery documentation](https://docs.fastly.com/products/pci-compliant-caching-and-delivery)
   * for details.
   *
   * Undefined if the response is not cached or the environment does not support the HTTP Cache hostcalls. May be modified prior to injection into the cache.
   */
  pci: boolean | undefined;
}

/**
 * @group Fetch API
 */
declare var Response: {
  prototype: Response;
  new (body?: BodyInit | null, init?: ResponseInit): Response;
  // error(): Response;
  redirect(url: string | URL, status?: number): Response;
  json(data: any, init?: ResponseInit): Response;
};

/**
 * @group Streams API
 */
type ReadableStreamReader<T> = ReadableStreamDefaultReader<T>;
// type ReadableStreamReader<T> = ReadableStreamDefaultReader<T> | ReadableStreamBYOBReader;
/**
 * @group Streams API
 */
type ReadableStreamController<T> = ReadableStreamDefaultController<T>;
// type ReadableStreamController<T> = ReadableStreamDefaultController<T> | ReadableByteStreamController;

/**
 * @group Streams API
 */
interface UnderlyingSinkAbortCallback {
  (reason?: any): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface UnderlyingSinkCloseCallback {
  (): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface UnderlyingSinkStartCallback {
  (controller: WritableStreamDefaultController): any;
}

/**
 * @group Streams API
 */
interface UnderlyingSinkWriteCallback<W> {
  (
    chunk: W,
    controller: WritableStreamDefaultController,
  ): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface UnderlyingSourceCancelCallback {
  (reason?: any): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface UnderlyingSourcePullCallback<R> {
  (controller: ReadableStreamController<R>): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface UnderlyingSourceStartCallback<R> {
  (controller: ReadableStreamController<R>): any;
}

/**
 * @group Streams API
 */
interface UnderlyingSink<W = any> {
  abort?: UnderlyingSinkAbortCallback;
  close?: UnderlyingSinkCloseCallback;
  start?: UnderlyingSinkStartCallback;
  type?: undefined;
  write?: UnderlyingSinkWriteCallback<W>;
}

/**
 * @group Streams API
 */
interface UnderlyingSource<R = any> {
  autoAllocateChunkSize?: number;
  cancel?: UnderlyingSourceCancelCallback;
  pull?: UnderlyingSourcePullCallback<R>;
  start?: UnderlyingSourceStartCallback<R>;
  type?: ReadableStreamType;
}

/**
 * @group Streams API
 */
type ReadableStreamType = 'bytes';

/**
 * @group Streams API
 */
interface StreamPipeOptions {
  preventAbort?: boolean;
  preventCancel?: boolean;
  /**
   * Pipes this readable stream to a given writable stream destination. The way in which the piping process behaves under various error conditions can be customized with a number of passed options. It returns a promise that fulfills when the piping process completes successfully, or rejects if any errors were encountered.
   *
   * Piping a stream will lock it for the duration of the pipe, preventing any other consumer from acquiring a reader.
   *
   * Errors and closures of the source and destination streams propagate as follows:
   *
   * An error in this source readable stream will abort destination, unless preventAbort is truthy. The returned promise will be rejected with the source's error, or with any error that occurs during aborting the destination.
   *
   * An error in destination will cancel this source readable stream, unless preventCancel is truthy. The returned promise will be rejected with the destination's error, or with any error that occurs during canceling the source.
   *
   * When this source readable stream closes, destination will be closed, unless preventClose is truthy. The returned promise will be fulfilled once this process completes, unless an error is encountered while closing the destination, in which case it will be rejected with that error.
   *
   * If destination starts out closed or closing, this source readable stream will be canceled, unless preventCancel is true. The returned promise will be rejected with an error indicating piping to a closed stream failed, or with any error that occurs during canceling the source.
   *
   * The signal option can be set to an AbortSignal to allow aborting an ongoing pipe operation via the corresponding AbortController. In this case, this source readable stream will be canceled, and destination aborted, unless the respective options preventCancel or preventAbort are set.
   */
  preventClose?: boolean;
  // signal?: AbortSignal;
}

/**
 * @group Streams API
 */
interface QueuingStrategySize<T = any> {
  (chunk: T): number;
}

/**
 * @group Streams API
 */
interface QueuingStrategy<T = any> {
  highWaterMark?: number;
  size?: QueuingStrategySize<T>;
}

/**
 * @group Streams API
 */
interface QueuingStrategyInit {
  /**
   * Creates a new ByteLengthQueuingStrategy with the provided high water mark.
   *
   * Note that the provided high water mark will not be validated ahead of time. Instead, if it is negative, NaN, or not a number, the resulting ByteLengthQueuingStrategy will cause the corresponding stream constructor to throw.
   */
  highWaterMark: number;
}

/**
 * @group Streams API
 */
interface ReadableStreamDefaultReadDoneResult {
  done: true;
  value?: undefined;
}

/**
 * @group Streams API
 */
interface ReadableStreamDefaultReadValueResult<T> {
  done: false;
  value: T;
}

/**
 * @group Streams API
 */
type ReadableStreamDefaultReadResult<T> =
  | ReadableStreamDefaultReadValueResult<T>
  | ReadableStreamDefaultReadDoneResult;

/**
 * @group Streams API
 */
interface ReadableWritablePair<R = any, W = any> {
  readable: ReadableStream<R>;
  /**
   * Provides a convenient, chainable way of piping this readable stream through a transform stream (or any other \{ writable, readable \} pair). It simply pipes the stream into the writable side of the supplied pair, and returns the readable side for further use.
   *
   * Piping a stream will lock it for the duration of the pipe, preventing any other consumer from acquiring a reader.
   */
  writable: WritableStream<W>;
}

/**
 * This Streams API interface represents a readable stream of byte data. The Fetch API offers a concrete instance of a ReadableStream through the body property of a Response object.
 * @group Streams API
 */
interface ReadableStream<R = any> {
  readonly locked: boolean;
  cancel(reason?: any): Promise<void>;
  getReader(): ReadableStreamDefaultReader<R>;
  pipeThrough<T>(
    transform: ReadableWritablePair<T, R>,
    options?: StreamPipeOptions,
  ): ReadableStream<T>;
  pipeTo(dest: WritableStream<R>, options?: StreamPipeOptions): Promise<void>;
  tee(): [ReadableStream<R>, ReadableStream<R>];
}

/**
 * The ReadableStream class as [specified by WHATWG](https://streams.spec.whatwg.org/#rs-class)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream | ReadableStream on MDN}
 * @group Streams API
 */
declare var ReadableStream: {
  prototype: ReadableStream;
  new <R = any>(
    underlyingSource?: UnderlyingSource<R>,
    strategy?: QueuingStrategy<R>,
  ): ReadableStream<R>;
};

/**
 * @group Streams API
 */
interface ReadableStreamDefaultController<R = any> {
  readonly desiredSize: number | null;
  close(): void;
  enqueue(chunk: R): void;
  error(e?: any): void;
}

/**
 * @group Streams API
 */
declare var ReadableStreamDefaultController: {
  prototype: ReadableStreamDefaultController;
  new (): ReadableStreamDefaultController;
};

/**
 * @group Streams API
 */
interface ReadableStreamDefaultReader<R = any>
  extends ReadableStreamGenericReader {
  read(): Promise<ReadableStreamDefaultReadResult<R>>;
  releaseLock(): void;
}

/**
 * @group Streams API
 */
declare var ReadableStreamDefaultReader: {
  prototype: ReadableStreamDefaultReader;
  new <R = any>(stream: ReadableStream<R>): ReadableStreamDefaultReader<R>;
};

/**
 * @group Streams API
 */
interface ReadableStreamGenericReader {
  readonly closed: Promise<undefined>;
  cancel(reason?: any): Promise<void>;
}

/**
 * This Streams API interface provides a standard abstraction for writing streaming data to a destination, known as a sink. This object comes with built-in backpressure and queuing.
 * @group Streams API
 */
interface WritableStream<W = any> {
  readonly locked: boolean;
  abort(reason?: any): Promise<void>;
  getWriter(): WritableStreamDefaultWriter<W>;
}

/**
 * The WritableStream class as [specified by WHATWG](https://streams.spec.whatwg.org/#ws-class)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/WritableStream | WritableStream on MDN}
 * @group Streams API
 */
declare var WritableStream: {
  prototype: WritableStream;
  new <W = any>(
    underlyingSink?: UnderlyingSink<W>,
    strategy?: QueuingStrategy<W>,
  ): WritableStream<W>;
};

/**
 * This Streams API interface represents a controller allowing control of a WritableStream's state. When constructing a WritableStream, the underlying sink is given a corresponding WritableStreamDefaultController instance to manipulate.
 * @group Streams API
 */
interface WritableStreamDefaultController {
  error(e?: any): void;
}

/**
 * @group Streams API
 */
declare var WritableStreamDefaultController: {
  prototype: WritableStreamDefaultController;
  new (): WritableStreamDefaultController;
};

/**
 * This Streams API interface is the object returned by WritableStream.getWriter() and once created locks the < writer to the WritableStream ensuring that no other streams can write to the underlying sink.
 * @group Streams API
 */
interface WritableStreamDefaultWriter<W = any> {
  readonly closed: Promise<undefined>;
  readonly desiredSize: number | null;
  readonly ready: Promise<undefined>;
  abort(reason?: any): Promise<void>;
  close(): Promise<void>;
  releaseLock(): void;
  write(chunk: W): Promise<void>;
}

/**
 * @group Streams API
 */
declare var WritableStreamDefaultWriter: {
  prototype: WritableStreamDefaultWriter;
  new <W = any>(stream: WritableStream<W>): WritableStreamDefaultWriter<W>;
};

/**
 * @group Streams API
 */
interface TransformStream<I = any, O = any> {
  readonly readable: ReadableStream<O>;
  readonly writable: WritableStream<I>;
}

/**
 * The TransformStream class as [specified by WHATWG](https://streams.spec.whatwg.org/#ts-class)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/TransformStream | TransformStream on MDN}
 * @group Streams API
 */

declare var TransformStream: {
  prototype: TransformStream;
  new <I = any, O = any>(
    transformer?: Transformer<I, O>,
    writableStrategy?: QueuingStrategy<I>,
    readableStrategy?: QueuingStrategy<O>,
  ): TransformStream<I, O>;
};

/**
 * @group Streams API
 */
interface TransformStreamDefaultController<O = any> {
  readonly desiredSize: number | null;
  enqueue(chunk?: O): void;
  error(reason?: any): void;
  terminate(): void;
}

/**
 * @group Streams API
 */
declare var TransformStreamDefaultController: {
  prototype: TransformStreamDefaultController;
  new (): TransformStreamDefaultController;
};

/**
 * @group Streams API
 */
interface Transformer<I = any, O = any> {
  flush?: TransformerFlushCallback<O>;
  readableType?: undefined;
  start?: TransformerStartCallback<O>;
  transform?: TransformerTransformCallback<I, O>;
  writableType?: undefined;
}

/**
 * @group Streams API
 */
interface TransformerFlushCallback<O> {
  (controller: TransformStreamDefaultController<O>): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface TransformerStartCallback<O> {
  (controller: TransformStreamDefaultController<O>): void | PromiseLike<void>;
}

/**
 * @group Streams API
 */
interface TransformerTransformCallback<I, O> {
  (
    chunk: I,
    controller: TransformStreamDefaultController<O>,
  ): void | PromiseLike<void>;
}

/**
 * @group Fetch API
 */
type HeadersInit = Headers | string[][] | Record<string, string>;

/**
 * The Headers class as [specified by WHATWG](https://fetch.spec.whatwg.org/#headers-class)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/Headers | Headers on MDN}
 * @group Fetch API
 */
interface Headers {
  append(name: string, value: string): void;
  delete(name: string): void;
  get(name: string): string | null;
  has(name: string): boolean;
  set(name: string, value: string): void;
  forEach(
    callbackfn: (value: string, key: string, parent: Headers) => void,
    thisArg?: any,
  ): void;
  // Iterable methods
  entries(): IterableIterator<[string, string]>;
  keys(): IterableIterator<string>;
  values(): IterableIterator<string>;
  [Symbol.iterator](): Iterator<[string, string]>;
}

/**
 * @group Fetch API
 */
declare var Headers: {
  prototype: Headers;
  new (init?: HeadersInit): Headers;
};

/**
 * The atob() function decodes a string of data which has been encoded using Base64 encoding.
 *
 * @param data A binary string (i.e., a string in which each character in the string is treated as a byte of binary data) containing base64-encoded data.
 * @returns An ASCII string containing decoded data from `data`.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/atob | atob on MDN}
 * @group Encoding API
 */
declare function atob(data: string): string;

/**
 *  The btoa() method creates a Base64-encoded ASCII string from a binary string (i.e., a string in which each character in the string is treated as a byte of binary data).
 * @param data The binary string to encode.
 * @returns  An ASCII string containing the Base64 representation of `data`.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/btoa | btoa on MDN}
 * @group Encoding API
 */
declare function btoa(data: string): string;

/**
 * The setTimeout() method sets a timer which calls a function once the timer expires.
 *
 * @param callback A function to be called after the timer expires.
 * @param delay The time, in milliseconds, that the timer should wait before calling the specified function. Defaults to 0 if not specified.
 * @param args Additional arguments which are passed through to the callback function.
 * @returns A numeric, non-zero value which identifies the timer created; this value can be passed to clearTimeout() to cancel the timeout.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/setTimeout | setTimeout on MDN}
 * @group Timers
 */
declare function setTimeout<TArgs extends any[]>(
  callback: (...args: TArgs) => void,
  delay?: number,
  ...args: TArgs
): number;

/**
 * The clearTimeout() method cancels a timeout previously established by calling setTimeout(). If the parameter provided does not identify a previously established action, this method does nothing.
 * @param timeoutID The identifier of the timeout you want to cancel. This ID was returned by the corresponding call to setTimeout().
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/clearTimeout | clearTimeout on MDN}
 * @group Timers
 */
declare function clearTimeout(timeoutID?: number): void;

/**
 * The setInterval() method repeatedly calls a function, with a fixed time delay between each call.
 * This method returns an interval ID which uniquely identifies the interval, so you can remove it later by calling clearInterval().
 *
 * @param callback A function to be called every delay milliseconds. The first call happens after delay milliseconds.
 * @param delay The time, in milliseconds, that the timer should delay in between calls of the specified function. Defaults to 0 if not specified.
 * @param args Additional arguments which are passed through to the callback function.
 * @returns A numeric, non-zero value which identifies the timer created; this value can be passed to clearInterval() to cancel the interval.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/setInterval | setInterval on MDN}
 * @group Timers
 */
declare function setInterval<TArgs extends any[]>(
  callback: (...args: TArgs) => void,
  delay?: number,
  ...args: TArgs
): number;

/**
 * The clearInterval() method cancels a timed, repeating action which was previously established by a call to setInterval(). If the parameter provided does not identify a previously established action, this method does nothing.
 * @param intervalID The identifier of the repeated action you want to cancel. This ID was returned by the corresponding call to setInterval().
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/clearInterval | clearInterval on MDN}
 * @group Timers
 */
declare function clearInterval(intervalID?: number): void;

/**
 * Fetch resources from backends.
 *
 * **Note**: Fastly Compute requires all outgoing requests to go to a predefined
 * {@link https://developer.fastly.com/reference/glossary#term-backend | backend}, passed in
 * via the {@link RequestInit.backend | backend} property on the `init` object.
 *
 * **Note**: Can only be used when processing requests, not during build-time initialization.
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch | fetch on MDN}
 *
 * @param resource - The resource to fetch, either a URL string or a {@link Request} object
 * @param init - An object containing settings to apply to the request
 * @group Fetch API
 */
declare function fetch(
  input: RequestInfo | URL,
  init?: RequestInit,
): Promise<Response>;

/**
 * @group Scheduling
 */
interface VoidFunction {
  (): void;
}

/**
 * @group Scheduling
 */
declare function queueMicrotask(callback: VoidFunction): void;

/**
 * @group DOM APIs
 */
declare function structuredClone(
  value: any,
  options?: StructuredSerializeOptions,
): any;

/**
 * @group DOM APIs
 */
interface StructuredSerializeOptions {
  transfer?: Transferable[];
}

/**
 * @group DOM APIs
 */
type Transferable = ArrayBuffer;
// type Transferable = ArrayBuffer | MessagePort | ImageBitmap;

/**
 * @group Web APIs
 */
interface WorkerLocation {
  readonly hash: string;
  readonly host: string;
  readonly hostname: string;
  readonly href: string;
  toString(): string;
  readonly origin: string;
  readonly pathname: string;
  readonly port: string;
  readonly protocol: string;
  readonly search: string;
}

/**
 * The WorkerLocation class as [specified by WHATWG](https://html.spec.whatwg.org/multipage/workers.html#worker-locations)
 *
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/WorkerLocation | WorkerLocation on MDN}
 * @group Web APIs
 */
declare var WorkerLocation: {
  prototype: WorkerLocation;
  new (): WorkerLocation;
};

/**
 * @group Web APIs
 */
declare var location: WorkerLocation;

interface Algorithm {
  name: string;
}

type AlgorithmIdentifier = Algorithm | string;

type BufferSource = ArrayBufferView | ArrayBuffer;

declare class SubtleCrypto {
  constructor();
  // decrypt(algorithm: AlgorithmIdentifier | RsaOaepParams | AesCtrParams | AesCbcParams | AesGcmParams, key: CryptoKey, data: BufferSource): Promise<ArrayBuffer>;
  // deriveBits(algorithm: AlgorithmIdentifier | EcdhKeyDeriveParams | HkdfParams | Pbkdf2Params, baseKey: CryptoKey, length: number): Promise<ArrayBuffer>;
  // deriveKey(algorithm: AlgorithmIdentifier | EcdhKeyDeriveParams | HkdfParams | Pbkdf2Params, baseKey: CryptoKey, derivedKeyType: AlgorithmIdentifier | AesDerivedKeyParams | HmacImportParams | HkdfParams | Pbkdf2Params, extractable: boolean, keyUsages: KeyUsage[]): Promise<CryptoKey>;
  digest(
    algorithm: AlgorithmIdentifier,
    data: BufferSource,
  ): Promise<ArrayBuffer>;
  // encrypt(algorithm: AlgorithmIdentifier | RsaOaepParams | AesCtrParams | AesCbcParams | AesGcmParams, key: CryptoKey, data: BufferSource): Promise<ArrayBuffer>;
  // exportKey(format: "jwk", key: CryptoKey): Promise<JsonWebKey>;
  // exportKey(format: Exclude<KeyFormat, "jwk">, key: CryptoKey): Promise<ArrayBuffer>;
  // generateKey(algorithm: RsaHashedKeyGenParams | EcKeyGenParams, extractable: boolean, keyUsages: ReadonlyArray<KeyUsage>): Promise<CryptoKeyPair>;
  // generateKey(algorithm: AesKeyGenParams | HmacKeyGenParams | Pbkdf2Params, extractable: boolean, keyUsages: ReadonlyArray<KeyUsage>): Promise<CryptoKey>;
  // generateKey(algorithm: AlgorithmIdentifier, extractable: boolean, keyUsages: KeyUsage[]): Promise<CryptoKeyPair | CryptoKey>;
  // importKey(format: "jwk", keyData: JsonWebKey, algorithm: AlgorithmIdentifier | RsaHashedImportParams | EcKeyImportParams | HmacImportParams | AesKeyAlgorithm, extractable: boolean, keyUsages: ReadonlyArray<KeyUsage>): Promise<CryptoKey>;
  importKey(
    format: 'jwk',
    keyData: JsonWebKey,
    algorithm: AlgorithmIdentifier | RsaHashedImportParams | EcKeyImportParams,
    extractable: boolean,
    keyUsages: ReadonlyArray<KeyUsage>,
  ): Promise<CryptoKey>;
  importKey(
    format: Exclude<KeyFormat, 'jwk'>,
    keyData: BufferSource,
    algorithm:
      | AlgorithmIdentifier
      | RsaHashedImportParams
      // | EcKeyImportParams
      | HmacImportParams,
    // | AesKeyAlgorithm
    extractable: boolean,
    keyUsages: KeyUsage[],
  ): Promise<CryptoKey>;
  // sign(algorithm: AlgorithmIdentifier | RsaPssParams | EcdsaParams, key: CryptoKey, data: BufferSource): Promise<ArrayBuffer>;
  sign(
    algorithm: AlgorithmIdentifier,
    key: CryptoKey,
    data: BufferSource,
  ): Promise<ArrayBuffer>;
  // unwrapKey(format: KeyFormat, wrappedKey: BufferSource, unwrappingKey: CryptoKey, unwrapAlgorithm: AlgorithmIdentifier | RsaOaepParams | AesCtrParams | AesCbcParams | AesGcmParams, unwrappedKeyAlgorithm: AlgorithmIdentifier | RsaHashedImportParams | EcKeyImportParams | HmacImportParams | AesKeyAlgorithm, extractable: boolean, keyUsages: KeyUsage[]): Promise<CryptoKey>;
  // verify(algorithm: AlgorithmIdentifier | RsaPssParams | EcdsaParams, key: CryptoKey, signature: BufferSource, data: BufferSource): Promise<boolean>;
  verify(
    algorithm: AlgorithmIdentifier,
    key: CryptoKey,
    signature: BufferSource,
    data: BufferSource,
  ): Promise<boolean>;
  // wrapKey(format: KeyFormat, key: CryptoKey, wrappingKey: CryptoKey, wrapAlgorithm: AlgorithmIdentifier | RsaOaepParams | AesCtrParams | AesCbcParams | AesGcmParams): Promise<ArrayBuffer>;
}

interface HmacImportParams extends Algorithm {
  hash: HashAlgorithmIdentifier;
  length?: number;
}

interface RsaHashedImportParams extends Algorithm {
  hash: HashAlgorithmIdentifier;
}
type HashAlgorithmIdentifier = AlgorithmIdentifier;

interface EcKeyImportParams {
  name: 'ECDSA';
  namedCurve: 'P-256' | 'P-384' | 'P-521';
}

interface JsonWebKey {
  alg?: string;
  crv?: string;
  d?: string;
  dp?: string;
  dq?: string;
  e?: string;
  ext?: boolean;
  k?: string;
  key_ops?: string[];
  kty?: string;
  n?: string;
  oth?: RsaOtherPrimesInfo[];
  p?: string;
  q?: string;
  qi?: string;
  use?: string;
  x?: string;
  y?: string;
}

interface RsaOtherPrimesInfo {
  d?: string;
  r?: string;
  t?: string;
}

/**
 * The Crypto interface as [specified by WHATWG](https://w3c.github.io/webcrypto/#crypto-interface)
 * Basic cryptography features available in the current context. It allows access to a cryptographically strong random number generator and to cryptographic primitives.
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/Crypto | Crypto on MDN}
 * @group Web Crypto APIs
 */
interface Crypto {
  readonly subtle: SubtleCrypto;
  getRandomValues<T extends ArrayBufferView | null>(array: T): T;
  randomUUID(): string;
}

/**
 * @group Web Crypto APIs
 */
declare var Crypto: {
  prototype: Crypto;
  new (): Crypto;
};

/**
 * @group Web Crypto APIs
 */
declare var crypto: Crypto;

/**
 * The CryptoKey dictionary of the Web Crypto API represents a cryptographic key.
 * Available only in secure contexts.
 *
 * [MDN Reference](https://developer.mozilla.org/docs/Web/API/CryptoKey)
 */
interface CryptoKey {
  /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/CryptoKey/algorithm) */
  readonly algorithm: KeyAlgorithm;
  /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/CryptoKey/extractable) */
  readonly extractable: boolean;
  /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/CryptoKey/type) */
  readonly type: KeyType;
  /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/CryptoKey/usages) */
  readonly usages: KeyUsage[];
}

declare var CryptoKey: {
  prototype: CryptoKey;
  new (): CryptoKey;
};

interface KeyAlgorithm {
  name: string;
}

type KeyFormat =
  | 'jwk'
  // | "pkcs8"
  | 'raw';
// | "spki";
type KeyType = 'private' | 'public' | 'secret';
type KeyUsage =
  | 'decrypt'
  | 'deriveBits'
  | 'deriveKey'
  | 'encrypt'
  | 'sign'
  | 'unwrapKey'
  | 'verify'
  | 'wrapKey';

/**
 * EventTarget is a DOM interface implemented by objects that can receive events and may have listeners for them.
 *
 * [MDN Reference](https://developer.mozilla.org/docs/Web/API/EventTarget)
 * @group DOM Events
 */
interface EventTarget {
  //addEventListener(type: string, callback: EventListenerOrEventListenerObject | null, options?: AddEventListenerOptions | boolean): void;
  //dispatchEvent(event: Event): boolean;
  //removeEventListener(type: string, callback: EventListenerOrEventListenerObject | null, options?: EventListenerOptions | boolean): void;
}

/**
 * Provides access to performance-related information for the current page. It's part of the High Resolution Time API, but is enhanced by the Performance Timeline API, the Navigation Timing API, the User Timing API, and the Resource Timing API.
 *
 * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Performance)
 * @group Performance APIs
 */
interface Performance extends EventTarget {
  /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/Performance/timeOrigin) */
  readonly timeOrigin: DOMHighResTimeStamp;
  /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/Performance/now) */
  now(): DOMHighResTimeStamp;
}

/**
 * @group Performance APIs
 */
declare var Performance: {
  prototype: Performance;
  new (): Performance;
};

/**
 * @group Performance APIs
 */
declare var performance: Performance;

type DOMHighResTimeStamp = number;