1'use strict';
2
3Object.defineProperty(exports, "__esModule", {
4    value: true
5});
6exports.default = seq;
7
8var _reduce = require('./reduce.js');
9
10var _reduce2 = _interopRequireDefault(_reduce);
11
12var _wrapAsync = require('./internal/wrapAsync.js');
13
14var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
15
16var _promiseCallback = require('./internal/promiseCallback.js');
17
18function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
19
20/**
21 * Version of the compose function that is more natural to read. Each function
22 * consumes the return value of the previous function. It is the equivalent of
23 * [compose]{@link module:ControlFlow.compose} with the arguments reversed.
24 *
25 * Each function is executed with the `this` binding of the composed function.
26 *
27 * @name seq
28 * @static
29 * @memberOf module:ControlFlow
30 * @method
31 * @see [async.compose]{@link module:ControlFlow.compose}
32 * @category Control Flow
33 * @param {...AsyncFunction} functions - the asynchronous functions to compose
34 * @returns {Function} a function that composes the `functions` in order
35 * @example
36 *
37 * // Requires lodash (or underscore), express3 and dresende's orm2.
38 * // Part of an app, that fetches cats of the logged user.
39 * // This example uses `seq` function to avoid overnesting and error
40 * // handling clutter.
41 * app.get('/cats', function(request, response) {
42 *     var User = request.models.User;
43 *     async.seq(
44 *         User.get.bind(User),  // 'User.get' has signature (id, callback(err, data))
45 *         function(user, fn) {
46 *             user.getCats(fn);      // 'getCats' has signature (callback(err, data))
47 *         }
48 *     )(req.session.user_id, function (err, cats) {
49 *         if (err) {
50 *             console.error(err);
51 *             response.json({ status: 'error', message: err.message });
52 *         } else {
53 *             response.json({ status: 'ok', message: 'Cats found', data: cats });
54 *         }
55 *     });
56 * });
57 */
58function seq(...functions) {
59    var _functions = functions.map(_wrapAsync2.default);
60    return function (...args) {
61        var that = this;
62
63        var cb = args[args.length - 1];
64        if (typeof cb == 'function') {
65            args.pop();
66        } else {
67            cb = (0, _promiseCallback.promiseCallback)();
68        }
69
70        (0, _reduce2.default)(_functions, args, (newargs, fn, iterCb) => {
71            fn.apply(that, newargs.concat((err, ...nextargs) => {
72                iterCb(err, nextargs);
73            }));
74        }, (err, results) => cb(err, ...results));
75
76        return cb[_promiseCallback.PROMISE_SYMBOL];
77    };
78}
79module.exports = exports['default'];