schedulerjs/dist/sequence.js

A promise execution flow control library

'use strict';

Object.defineProperty(exports, '__esModule', {
    value: true
});

var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();

var _get = function get(_x, _x2, _x3) { var _again = true; _function: while (_again) { var object = _x, property = _x2, receiver = _x3; desc = parent = getter = undefined; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x = parent; _x2 = property; _x3 = receiver; _again = true; continue _function; } } else if ('value' in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }

function _inherits(subClass, superClass) { if (typeof superClass !== 'function' && superClass !== null) { throw new TypeError('Super expression must either be null or a function, not ' + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

var _events = require('events');

/**
 * Sequential promises
 */

var Sequence = (function (_EventEmitter) {
    _inherits(Sequence, _EventEmitter);

    /**
     * Initializes the object
     */

    function Sequence() {
        _classCallCheck(this, Sequence);

        _get(Object.getPrototypeOf(Sequence.prototype), 'constructor', this).call(this);

        this.started = false;
        this.queue = [];
        this.pos = 0;
    }

    /**
     * Adds a function to the queue
     * @param  {Function|Sequence} callback A function returning a promise or another sequence
     * @return {Function} This object (chaining)
     */

    _createClass(Sequence, [{
        key: 'next',
        value: function next(callback) {
            if (callback instanceof Sequence) {
                var _queue;

                var otherSequenceToPush = callback.queue.slice(callback.pos);
                (_queue = this.queue).push.apply(_queue, _toConsumableArray(otherSequenceToPush));
            } else {
                this.queue.push(callback);
            }

            return this;
        }

        /**
         * Adds a delay function to the queue
         * @param  {Number} number The timeout amount
         * @return {Function} This object (chaining)
         */
    }, {
        key: 'delay',
        value: function delay(number) {
            var timeoutPromise = function timeoutPromise() {
                return new Promise(function (resolve) {
                    setTimeout(function () {
                        resolve();
                    }, number);
                });
            };

            return this.next(timeoutPromise);
        }

        /**
         * Stops the sequence after the next test is done
         */
    }, {
        key: 'stop',
        value: function stop() {
            this.stopped = true;
            this.emit('stopped');
        }

        /**
         * Starts the queue
         */
    }, {
        key: 'start',
        value: function start() {
            var _this = this;

            // use nextTick to allow events after start
            process.nextTick(function () {
                if (!_this.started) {
                    _this.started = true;
                    _this.emit('started');
                } else {
                    _this.emit('next', _this.pos, _this.queue.length);
                }

                if (_this.queue.length - _this.pos === 0) {
                    _this.emit('finished');

                    return;
                }

                var returnValue = _this.queue[_this.pos]();

                if (returnValue instanceof Promise) {
                    returnValue.then(function () {
                        _this._callNext();
                    })['catch'](function (reason) {
                        _this.emit('error', reason);
                    });
                } else {
                    _this._callNext();
                }
            });
        }

        /**
         * Call the next on the queue, or not if stopped
         * @private
         */
    }, {
        key: '_callNext',
        value: function _callNext() {
            if (this.stopped) {
                return;
            }

            ++this.pos;
            this.start();
        }
    }]);

    return Sequence;
})(_events.EventEmitter);

exports['default'] = Sequence;
module.exports = exports['default'];