lit-html/lit-html.d.ts

/**
 * @license
 * Copyright 2017 Google LLC
 * SPDX-License-Identifier: BSD-3-Clause
 */
/// <reference types="trusted-types" />
import type { Directive } from './directive.js';
/**
 * Used to sanitize any value before it is written into the DOM. This can be
 * used to implement a security policy of allowed and disallowed values in
 * order to prevent XSS attacks.
 *
 * One way of using this callback would be to check attributes and properties
 * against a list of high risk fields, and require that values written to such
 * fields be instances of a class which is safe by construction. Closure's Safe
 * HTML Types is one implementation of this technique (
 * https://github.com/google/safe-html-types/blob/master/doc/safehtml-types.md).
 * The TrustedTypes polyfill in API-only mode could also be used as a basis
 * for this technique (https://github.com/WICG/trusted-types).
 *
 * @param node The HTML node (usually either a #text node or an Element) that
 *     is being written to. Note that this is just an exemplar node, the write
 *     may take place against another instance of the same class of node.
 * @param name The name of an attribute or property (for example, 'href').
 * @param type Indicates whether the write that's about to be performed will
 *     be to a property or a node.
 * @return A function that will sanitize this class of writes.
 */
export declare type SanitizerFactory = (node: Node, name: string, type: 'property' | 'attribute') => ValueSanitizer;
/**
 * A function which can sanitize values that will be written to a specific kind
 * of DOM sink.
 *
 * See SanitizerFactory.
 *
 * @param value The value to sanitize. Will be the actual value passed into
 *     the lit-html template literal, so this could be of any type.
 * @return The value to write to the DOM. Usually the same as the input value,
 *     unless sanitization is needed.
 */
export declare type ValueSanitizer = (value: unknown) => unknown;
/** TemplateResult types */
declare const HTML_RESULT = 1;
declare const SVG_RESULT = 2;
declare type ResultType = typeof HTML_RESULT | typeof SVG_RESULT;
/**
 * The return type of the template tag functions.
 */
export declare type TemplateResult<T extends ResultType = ResultType> = {
    ['_$litType$']: T;
    strings: TemplateStringsArray;
    values: unknown[];
};
export declare type HTMLTemplateResult = TemplateResult<typeof HTML_RESULT>;
export declare type SVGTemplateResult = TemplateResult<typeof SVG_RESULT>;
export interface CompiledTemplateResult {
    ['_$litType$']: CompiledTemplate;
    values: unknown[];
}
export interface CompiledTemplate extends Omit<Template, 'el'> {
    el?: HTMLTemplateElement;
    h: TrustedHTML;
}
/**
 * Interprets a template literal as an HTML template that can efficiently
 * render to and update a container.
 *
 * ```ts
 * const header = (title: string) => html`<h1>${title}</h1>`;
 * ```
 *
 * The `html` tag returns a description of the DOM to render as a value. It is
 * lazy, meaning no work is done until the template is rendered. When rendering,
 * if a template comes from the same expression as a previously rendered result,
 * it's efficiently updated instead of replaced.
 */
export declare const html: (strings: TemplateStringsArray, ...values: unknown[]) => TemplateResult<1>;
/**
 * Interprets a template literal as an SVG template that can efficiently
 * render to and update a container.
 */
export declare const svg: (strings: TemplateStringsArray, ...values: unknown[]) => TemplateResult<2>;
/**
 * A sentinel value that signals that a value was handled by a directive and
 * should not be written to the DOM.
 */
export declare const noChange: unique symbol;
/**
 * A sentinel value that signals a ChildPart to fully clear its content.
 *
 * ```ts
 * const button = html`${
 *  user.isAdmin
 *    ? html`<button>DELETE</button>`
 *    : nothing
 * }`;
 * ```
 *
 * Prefer using `nothing` over other falsy values as it provides a consistent
 * behavior between various expression binding contexts.
 *
 * In child expressions, `undefined`, `null`, `''`, and `nothing` all behave the
 * same and render no nodes. In attribute expressions, `nothing` _removes_ the
 * attribute, while `undefined` and `null` will render an empty string. In
 * property expressions `nothing` becomes `undefined`.
 */
export declare const nothing: unique symbol;
/**
 * Object specifying options for controlling lit-html rendering. Note that
 * while `render` may be called multiple times on the same `container` (and
 * `renderBefore` reference node) to efficiently update the rendered content,
 * only the options passed in during the first render are respected during
 * the lifetime of renders to that unique `container` + `renderBefore`
 * combination.
 */
export interface RenderOptions {
    /**
     * An object to use as the `this` value for event listeners. It's often
     * useful to set this to the host component rendering a template.
     */
    host?: object;
    /**
     * A DOM node before which to render content in the container.
     */
    renderBefore?: ChildNode | null;
    /**
     * Node used for cloning the template (`importNode` will be called on this
     * node). This controls the `ownerDocument` of the rendered DOM, along with
     * any inherited context. Defaults to the global `document`.
     */
    creationScope?: {
        importNode(node: Node, deep?: boolean): Node;
    };
    /**
     * The initial connected state for the top-level part being rendered. If no
     * `isConnected` option is set, `AsyncDirective`s will be connected by
     * default. Set to `false` if the initial render occurs in a disconnected tree
     * and `AsyncDirective`s should see `isConnected === false` for their initial
     * render. The `part.setConnected()` method must be used subsequent to initial
     * render to change the connected state of the part.
     */
    isConnected?: boolean;
}
/**
 * Renders a value, usually a lit-html TemplateResult, to the container.
 * @param value
 * @param container
 * @param options
 */
export declare const render: {
    (value: unknown, container: HTMLElement | DocumentFragment, options?: RenderOptions | undefined): RootPart;
    setSanitizer: (newSanitizer: SanitizerFactory) => void;
    createSanitizer: SanitizerFactory;
    _testOnlyClearSanitizerFactoryDoNotCallOrElse: () => void;
};
export interface DirectiveParent {
    _$parent?: DirectiveParent;
    _$isConnected: boolean;
    __directive?: Directive;
    __directives?: Array<Directive | undefined>;
}
declare class Template {
    constructor({ strings, ['_$litType$']: type }: TemplateResult, options?: RenderOptions);
    /** @nocollapse */
    static createElement(html: TrustedHTML, _options?: RenderOptions): HTMLTemplateElement;
}
export interface Disconnectable {
    _$parent?: Disconnectable;
    _$disconnectableChildren?: Set<Disconnectable>;
    _$isConnected: boolean;
}
declare function resolveDirective(part: ChildPart | AttributePart | ElementPart, value: unknown, parent?: DirectiveParent, attributeIndex?: number): unknown;
/**
 * An updateable instance of a Template. Holds references to the Parts used to
 * update the template instance.
 */
declare class TemplateInstance implements Disconnectable {
    constructor(template: Template, parent: ChildPart);
    get parentNode(): Node;
    get _$isConnected(): boolean;
    _clone(options: RenderOptions | undefined): Node;
    _update(values: Array<unknown>): void;
}
export declare type Part = ChildPart | AttributePart | PropertyPart | BooleanAttributePart | ElementPart | EventPart;
export type { ChildPart };
declare class ChildPart implements Disconnectable {
    readonly type = 2;
    readonly options: RenderOptions | undefined;
    _$committedValue: unknown;
    private _textSanitizer;
    get _$isConnected(): boolean;
    constructor(startNode: ChildNode, endNode: ChildNode | null, parent: TemplateInstance | ChildPart | undefined, options: RenderOptions | undefined);
    /**
     * The parent node into which the part renders its content.
     *
     * A ChildPart's content consists of a range of adjacent child nodes of
     * `.parentNode`, possibly bordered by 'marker nodes' (`.startNode` and
     * `.endNode`).
     *
     * - If both `.startNode` and `.endNode` are non-null, then the part's content
     * consists of all siblings between `.startNode` and `.endNode`, exclusively.
     *
     * - If `.startNode` is non-null but `.endNode` is null, then the part's
     * content consists of all siblings following `.startNode`, up to and
     * including the last child of `.parentNode`. If `.endNode` is non-null, then
     * `.startNode` will always be non-null.
     *
     * - If both `.endNode` and `.startNode` are null, then the part's content
     * consists of all child nodes of `.parentNode`.
     */
    get parentNode(): Node;
    /**
     * The part's leading marker node, if any. See `.parentNode` for more
     * information.
     */
    get startNode(): Node | null;
    /**
     * The part's trailing marker node, if any. See `.parentNode` for more
     * information.
     */
    get endNode(): Node | null;
    _$setValue(value: unknown, directiveParent?: DirectiveParent): void;
    private _insert;
    private _commitNode;
    private _commitText;
    private _commitTemplateResult;
    private _commitIterable;
}
/**
 * A top-level `ChildPart` returned from `render` that manages the connected
 * state of `AsyncDirective`s created throughout the tree below it.
 */
export interface RootPart extends ChildPart {
    /**
     * Sets the connection state for `AsyncDirective`s contained within this root
     * ChildPart.
     *
     * lit-html does not automatically monitor the connectedness of DOM rendered;
     * as such, it is the responsibility of the caller to `render` to ensure that
     * `part.setConnected(false)` is called before the part object is potentially
     * discarded, to ensure that `AsyncDirective`s have a chance to dispose of
     * any resources being held. If a `RootPart` that was prevously
     * disconnected is subsequently re-connected (and its `AsyncDirective`s should
     * re-connect), `setConnected(true)` should be called.
     *
     * @param isConnected Whether directives within this tree should be connected
     * or not
     */
    setConnected(isConnected: boolean): void;
}
export type { AttributePart };
declare class AttributePart implements Disconnectable {
    readonly type: 1 | 3 | 4 | 5;
    readonly element: HTMLElement;
    readonly name: string;
    readonly options: RenderOptions | undefined;
    /**
     * If this attribute part represents an interpolation, this contains the
     * static strings of the interpolation. For single-value, complete bindings,
     * this is undefined.
     */
    readonly strings?: ReadonlyArray<string>;
    protected _sanitizer: ValueSanitizer | undefined;
    get tagName(): string;
    get _$isConnected(): boolean;
    constructor(element: HTMLElement, name: string, strings: ReadonlyArray<string>, parent: Disconnectable, options: RenderOptions | undefined);
}
export type { PropertyPart };
declare class PropertyPart extends AttributePart {
    readonly type = 3;
}
export type { BooleanAttributePart };
declare class BooleanAttributePart extends AttributePart {
    readonly type = 4;
}
/**
 * An AttributePart that manages an event listener via add/removeEventListener.
 *
 * This part works by adding itself as the event listener on an element, then
 * delegating to the value passed to it. This reduces the number of calls to
 * add/removeEventListener if the listener changes frequently, such as when an
 * inline function is used as a listener.
 *
 * Because event options are passed when adding listeners, we must take case
 * to add and remove the part as a listener when the event options change.
 */
export type { EventPart };
declare class EventPart extends AttributePart {
    readonly type = 5;
    constructor(element: HTMLElement, name: string, strings: ReadonlyArray<string>, parent: Disconnectable, options: RenderOptions | undefined);
    handleEvent(event: Event): void;
}
export type { ElementPart };
declare class ElementPart implements Disconnectable {
    element: Element;
    readonly type = 6;
    _$committedValue: undefined;
    options: RenderOptions | undefined;
    constructor(element: Element, parent: Disconnectable, options: RenderOptions | undefined);
    get _$isConnected(): boolean;
    _$setValue(value: unknown): void;
}
/**
 * END USERS SHOULD NOT RELY ON THIS OBJECT.
 *
 * Private exports for use by other Lit packages, not intended for use by
 * external users.
 *
 * We currently do not make a mangled rollup build of the lit-ssr code. In order
 * to keep a number of (otherwise private) top-level exports  mangled in the
 * client side code, we export a _$LH object containing those members (or
 * helper methods for accessing private fields of those members), and then
 * re-export them for use in lit-ssr. This keeps lit-ssr agnostic to whether the
 * client-side code is being used in `dev` mode or `prod` mode.
 *
 * This has a unique name, to disambiguate it from private exports in
 * lit-element, which re-exports all of lit-html.
 *
 * @private
 */
export declare const _$LH: {
    _boundAttributeSuffix: string;
    _marker: string;
    _markerMatch: string;
    _HTML_RESULT: number;
    _getTemplateHtml: (strings: TemplateStringsArray, type: ResultType) => [TrustedHTML, Array<string | undefined>];
    _TemplateInstance: typeof TemplateInstance;
    _isIterable: (value: unknown) => value is Iterable<unknown>;
    _resolveDirective: typeof resolveDirective;
    _ChildPart: typeof ChildPart;
    _AttributePart: typeof AttributePart;
    _BooleanAttributePart: typeof BooleanAttributePart;
    _EventPart: typeof EventPart;
    _PropertyPart: typeof PropertyPart;
    _ElementPart: typeof ElementPart;
};
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