@types/retry/index.d.ts

export interface RetryOperation {
    /**
     * Returns an array of all errors that have been passed to `retryOperation.retry()` so far.
     * The returning array has the errors ordered chronologically based on when they were passed to
     * `retryOperation.retry()`, which means the first passed error is at index zero and the last is at the last index.
     */
    errors(): Error[];

    /**
     * A reference to the error object that occured most frequently.
     * Errors are compared using the `error.message` property.
     * If multiple error messages occured the same amount of time, the last error object with that message is returned.
     *
     * @return If no errors occured so far the value will be `null`.
     */
    mainError(): Error | null;

    /**
     * Defines the function that is to be retried and executes it for the first time right away.
     *
     * @param fn The function that is to be retried. `currentAttempt` represents the number of attempts
     * callback has been executed so far.
     * @param [timeoutOps.timeout] A timeout in milliseconds.
     * @param [timeoutOps.callback] Callback to execute when the operation takes longer than the timeout.
     */
    attempt(fn: (currentAttempt: number) => void, timeoutOps?: AttemptTimeoutOptions): void;

    /**
     * Returns `false` when no `error` value is given, or the maximum amount of retries has been reached.
     * Otherwise it returns `true`, and retries the operation after the timeout for the current attempt number.
     */
    retry(err?: Error): boolean;

    /**
     * Stops the operation being retried. Useful for aborting the operation on a fatal error etc.
     */
    stop(): void;

    /**
     * Resets the internal state of the operation object, so that you can call `attempt()` again as if
     * this was a new operation object.
     */
    reset(): void;

    /**
     * Returns an int representing the number of attempts it took to call `fn` before it was successful.
     */
    attempts(): number;
}

export interface AttemptTimeoutOptions {
    /**
     * A timeout in milliseconds.
     */
    timeout?: number | undefined;
    /**
     * Callback to execute when the operation takes longer than the timeout.
     */
    callback?(): void;
}

/**
 * Create a new RetryOperation object.
 *
 * @param [options.retries=10] The maximum amount of times to retry the operation.
 * @param [options.factor=2] The exponential factor to use.
 * @param [options.minTimeout=1000] The number of milliseconds before starting the first retry.
 * @param [options.maxTimeout=Infinity] The maximum number of milliseconds between two retries.
 * @param [options.randomize=false] Randomizes the timeouts by multiplying a factor between 1-2.
 * @param [options.forever=false] Wether to retry forever.
 * @param [options.unref=false] Wether to unref the setTimeout's.
 */
export function operation(options?: OperationOptions): RetryOperation;

export type OperationOptions = WrapOptions | number[];

export interface WrapOptions extends TimeoutsOptions {
    /**
     * Whether to retry forever.
     * @default false
     */
    forever?: boolean | undefined;
    /**
     * Whether to [unref](https://nodejs.org/api/timers.html#timers_unref) the setTimeout's.
     * @default false
     */
    unref?: boolean | undefined;
    /**
     * The maximum time (in milliseconds) that the retried operation is allowed to run.
     * @default Infinity
     */
    maxRetryTime?: number | undefined;
}

/** Get an array with timeouts and their return values in milliseconds. */
export function timeouts(options?: TimeoutsOptions): number[];

export interface TimeoutsOptions extends CreateTimeoutOptions {
    /**
     * The maximum amount of times to retry the operation.
     * @default 10
     */
    retries?: number | undefined;
}

/**
 * Create a new timeout (in milliseconds) based on the given parameters.
 *
 * @param attempt  Representing for which retry the timeout should be calculated.
 * @return timeout
 */
export function createTimeout(attempt: number, options?: CreateTimeoutOptions): number;

export interface CreateTimeoutOptions {
    /**
     * The exponential factor to use.
     * @default 2
     */
    factor?: number | undefined;
    /**
     * The number of milliseconds before starting the first retry.
     * @default 1000
     */
    minTimeout?: number | undefined;
    /**
     * The maximum number of milliseconds between two retries.
     * @default Infinity
     */
    maxTimeout?: number | undefined;
    /**
     * Randomizes the timeouts by multiplying a factor between 1-2.
     * @default false
     */
    randomize?: boolean | undefined;
}

/**
 * Wrap all functions of the object with retry.
 *
 * @param object The object to be wrapped
 * @param methods Methods which need to be wrapped
 */
export function wrap(object: object, methods?: string[]): void;
export function wrap(object: object, options?: WrapOptions, methods?: string[]): void;