async-wrappers/es/retry.js

A set of wrapper functions to perform debouncing, throttling, retrying etc.

import wait from './wait';
/**
 * @internal
 */

const defaultDelays = [// 10 seconds
10 * 1000, // 1 Minute
60 * 1000, // 5 Minutes
5 * 60 * 1000, // 10 Minutes
10 * 60 * 1000];
/**
 * Function for determining a how long to wait after the given attempt
 *
 * @category Retry
 */

/**
 * @internal
 */
const getDelayFn = times => {
  if (typeof times === 'function') {
    return times;
  }

  if (typeof times === 'number') {
    return () => times;
  }

  return attempt => times[Math.min(attempt, times.length - 1)];
};
/**
 * A function used to determine if to stop for the given retry attempt.
 *
 * Errors thrown by this function will cause retry to reject with the
 * errorTypes of retry errors
 *
 * @category Retry
 */


/**
 * @internal
 */
const getStopFn = stop => {
  if (typeof stop === 'function') {
    return stop;
  }

  return attempt => attempt >= stop;
};
/**
 * callback for [[retry]] to determine the arguments to
 * the function to retry.
 * @typeparam RetryFunction the type of function to retry.
 *
 * @category Retry
 */


/**
 * @internal
 */
const getArgsFn = args => {
  if (typeof args === 'function') {
    return args;
  }

  return () => args;
};
/**
 * Types of retry errors
 *
 * @category Retry
 */


/**
 * Base Class for all retry errors
 *
 * @category Retry
 */
export class RetryError extends Error {
  /**
   * The type of error
   */

  /**
   * The last error that occurred when retrying
   */
  constructor(type, message, error) {
    super(message);
    this.type = type;
    this.error = error;
  }

}
/**
 * The error given when retrying is cancelled
 *
 * @category Retry
 */

export class RetryCancelledError extends RetryError {
  constructor(message = 'Cancelled', error) {
    super('cancelled', message, error);
  }

}
/**
 * The error given when retrying stops
 *
 * @category Retry
 */

export class RetryStoppedError extends RetryError {
  constructor(message = 'Stopped', error) {
    super('stopped', message, error);
  }

}
/**
 * The return type of [[retry]]
 *
 * @category Retry
 */

/**
 * Retry the wrapped function according to the
 *
 * @param func the function to retry.
 * @param delay a delay in milliseconds, an array of millisecond delays or
 * [[RetryDelayCallback|callback]] to determine the delay before the next
 * attempt.
 *
 * @param stop the number of attempts, or [[RetryStopCallback|callback]] to
 * determine when retry should stop retrying `func`.
 * @param args an array or [[RetryArgumentsCallback|callback]] to
 * provide arguments to `func`
 *
 * @category Wrapper
 */
const retry = (func, delay = defaultDelays, stop = 10, args = []) => {
  const getNextDelay = getDelayFn(delay);
  const shouldStop = getStopFn(stop);
  const getArgs = getArgsFn(args);
  let attempt = 0;
  let finished = false;
  let cancelled = false;
  let cancelReason;
  let waiting;
  let previousDelay = 0;
  let currentError;

  const afterAwait = () => {
    if (finished || !cancelled) {
      return;
    }

    throw new RetryCancelledError(cancelReason, currentError);
  };

  const exec = async () => {
    while (!cancelled) {
      const args = await getArgs(attempt, previousDelay, currentError);
      afterAwait();

      try {
        const value = await func(...args);
        finished = true;
        return value;
      } catch (error) {
        currentError = error;
        afterAwait(); // how long to wait after the last attempt

        const delay = await getNextDelay(attempt, previousDelay, error);
        afterAwait();
        previousDelay = delay;
        attempt++;
        const stop = await shouldStop(attempt, delay, error);
        afterAwait(); // should we stop the next attempt?

        if (stop) {
          const reason = typeof stop === 'string' ? stop : undefined;
          finished = true;
          throw new RetryStoppedError(reason, error);
        }

        waiting = wait(delay);
        await waiting;
        waiting = undefined;
        afterAwait();
      }
    }
  };

  const result = exec();

  result.cancel = reason => {
    if (finished || cancelled) {
      return;
    }

    cancelled = true;
    cancelReason = reason;

    if (waiting) {
      waiting.stop();
    }
  };

  return result;
};

export default retry;