retryable.js

import retry from './retry.js'
import initialParams from './internal/initialParams.js'
import {default as wrapAsync, isAsync} from './internal/wrapAsync.js'
import { promiseCallback, PROMISE_SYMBOL } from './internal/promiseCallback.js'

/**
 * A close relative of [`retry`]{@link module:ControlFlow.retry}.  This method
 * wraps a task and makes it retryable, rather than immediately calling it
 * with retries.
 *
 * @name retryable
 * @static
 * @memberOf module:ControlFlow
 * @method
 * @see [async.retry]{@link module:ControlFlow.retry}
 * @category Control Flow
 * @param {Object|number} [opts = {times: 5, interval: 0}| 5] - optional
 * options, exactly the same as from `retry`, except for a `opts.arity` that
 * is the arity of the `task` function, defaulting to `task.length`
 * @param {AsyncFunction} task - the asynchronous function to wrap.
 * This function will be passed any arguments passed to the returned wrapper.
 * Invoked with (...args, callback).
 * @returns {AsyncFunction} The wrapped function, which when invoked, will
 * retry on an error, based on the parameters specified in `opts`.
 * This function will accept the same parameters as `task`.
 * @example
 *
 * async.auto({
 *     dep1: async.retryable(3, getFromFlakyService),
 *     process: ["dep1", async.retryable(3, function (results, cb) {
 *         maybeProcessData(results.dep1, cb);
 *     })]
 * }, callback);
 */
export default function retryable (opts, task) {
    if (!task) {
        task = opts;
        opts = null;
    }
    let arity = (opts && opts.arity) || task.length
    if (isAsync(task)) {
        arity += 1
    }
    var _task = wrapAsync(task);
    return initialParams((args, callback) => {
        if (args.length < arity - 1 || callback == null) {
            args.push(callback)
            callback = promiseCallback()
        }
        function taskFn(cb) {
            _task(...args, cb);
        }

        if (opts) retry(opts, taskFn, callback);
        else retry(taskFn, callback);

        return callback[PROMISE_SYMBOL]
    });
}