1'use strict';
2
3Object.defineProperty(exports, "__esModule", {
4  value: true
5});
6
7exports.default = function (worker, concurrency) {
8  var _worker = (0, _wrapAsync2.default)(worker);
9  return (0, _queue2.default)((items, cb) => {
10    _worker(items[0], cb);
11  }, concurrency, 1);
12};
13
14var _queue = require('./internal/queue.js');
15
16var _queue2 = _interopRequireDefault(_queue);
17
18var _wrapAsync = require('./internal/wrapAsync.js');
19
20var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
21
22function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
23
24module.exports = exports['default'];
25
26/**
27 * A queue of tasks for the worker function to complete.
28 * @typedef {Iterable} QueueObject
29 * @memberOf module:ControlFlow
30 * @property {Function} length - a function returning the number of items
31 * waiting to be processed. Invoke with `queue.length()`.
32 * @property {boolean} started - a boolean indicating whether or not any
33 * items have been pushed and processed by the queue.
34 * @property {Function} running - a function returning the number of items
35 * currently being processed. Invoke with `queue.running()`.
36 * @property {Function} workersList - a function returning the array of items
37 * currently being processed. Invoke with `queue.workersList()`.
38 * @property {Function} idle - a function returning false if there are items
39 * waiting or being processed, or true if not. Invoke with `queue.idle()`.
40 * @property {number} concurrency - an integer for determining how many `worker`
41 * functions should be run in parallel. This property can be changed after a
42 * `queue` is created to alter the concurrency on-the-fly.
43 * @property {number} payload - an integer that specifies how many items are
44 * passed to the worker function at a time. only applies if this is a
45 * [cargo]{@link module:ControlFlow.cargo} object
46 * @property {AsyncFunction} push - add a new task to the `queue`. Calls `callback`
47 * once the `worker` has finished processing the task. Instead of a single task,
48 * a `tasks` array can be submitted. The respective callback is used for every
49 * task in the list. Invoke with `queue.push(task, [callback])`,
50 * @property {AsyncFunction} unshift - add a new task to the front of the `queue`.
51 * Invoke with `queue.unshift(task, [callback])`.
52 * @property {AsyncFunction} pushAsync - the same as `q.push`, except this returns
53 * a promise that rejects if an error occurs.
54 * @property {AsyncFunction} unshiftAsync - the same as `q.unshift`, except this returns
55 * a promise that rejects if an error occurs.
56 * @property {Function} remove - remove items from the queue that match a test
57 * function.  The test function will be passed an object with a `data` property,
58 * and a `priority` property, if this is a
59 * [priorityQueue]{@link module:ControlFlow.priorityQueue} object.
60 * Invoked with `queue.remove(testFn)`, where `testFn` is of the form
61 * `function ({data, priority}) {}` and returns a Boolean.
62 * @property {Function} saturated - a function that sets a callback that is
63 * called when the number of running workers hits the `concurrency` limit, and
64 * further tasks will be queued.  If the callback is omitted, `q.saturated()`
65 * returns a promise for the next occurrence.
66 * @property {Function} unsaturated - a function that sets a callback that is
67 * called when the number of running workers is less than the `concurrency` &
68 * `buffer` limits, and further tasks will not be queued. If the callback is
69 * omitted, `q.unsaturated()` returns a promise for the next occurrence.
70 * @property {number} buffer - A minimum threshold buffer in order to say that
71 * the `queue` is `unsaturated`.
72 * @property {Function} empty - a function that sets a callback that is called
73 * when the last item from the `queue` is given to a `worker`. If the callback
74 * is omitted, `q.empty()` returns a promise for the next occurrence.
75 * @property {Function} drain - a function that sets a callback that is called
76 * when the last item from the `queue` has returned from the `worker`. If the
77 * callback is omitted, `q.drain()` returns a promise for the next occurrence.
78 * @property {Function} error - a function that sets a callback that is called
79 * when a task errors. Has the signature `function(error, task)`. If the
80 * callback is omitted, `error()` returns a promise that rejects on the next
81 * error.
82 * @property {boolean} paused - a boolean for determining whether the queue is
83 * in a paused state.
84 * @property {Function} pause - a function that pauses the processing of tasks
85 * until `resume()` is called. Invoke with `queue.pause()`.
86 * @property {Function} resume - a function that resumes the processing of
87 * queued tasks when the queue is paused. Invoke with `queue.resume()`.
88 * @property {Function} kill - a function that removes the `drain` callback and
89 * empties remaining tasks from the queue forcing it to go idle. No more tasks
90 * should be pushed to the queue after calling this function. Invoke with `queue.kill()`.
91 *
92 * @example
93 * const q = async.queue(worker, 2)
94 * q.push(item1)
95 * q.push(item2)
96 * q.push(item3)
97 * // queues are iterable, spread into an array to inspect
98 * const items = [...q] // [item1, item2, item3]
99 * // or use for of
100 * for (let item of q) {
101 *     console.log(item)
102 * }
103 *
104 * q.drain(() => {
105 *     console.log('all done')
106 * })
107 * // or
108 * await q.drain()
109 */
110
111/**
112 * Creates a `queue` object with the specified `concurrency`. Tasks added to the
113 * `queue` are processed in parallel (up to the `concurrency` limit). If all
114 * `worker`s are in progress, the task is queued until one becomes available.
115 * Once a `worker` completes a `task`, that `task`'s callback is called.
116 *
117 * @name queue
118 * @static
119 * @memberOf module:ControlFlow
120 * @method
121 * @category Control Flow
122 * @param {AsyncFunction} worker - An async function for processing a queued task.
123 * If you want to handle errors from an individual task, pass a callback to
124 * `q.push()`. Invoked with (task, callback).
125 * @param {number} [concurrency=1] - An `integer` for determining how many
126 * `worker` functions should be run in parallel.  If omitted, the concurrency
127 * defaults to `1`.  If the concurrency is `0`, an error is thrown.
128 * @returns {module:ControlFlow.QueueObject} A queue object to manage the tasks. Callbacks can be
129 * attached as certain properties to listen for specific events during the
130 * lifecycle of the queue.
131 * @example
132 *
133 * // create a queue object with concurrency 2
134 * var q = async.queue(function(task, callback) {
135 *     console.log('hello ' + task.name);
136 *     callback();
137 * }, 2);
138 *
139 * // assign a callback
140 * q.drain(function() {
141 *     console.log('all items have been processed');
142 * });
143 * // or await the end
144 * await q.drain()
145 *
146 * // assign an error callback
147 * q.error(function(err, task) {
148 *     console.error('task experienced an error');
149 * });
150 *
151 * // add some items to the queue
152 * q.push({name: 'foo'}, function(err) {
153 *     console.log('finished processing foo');
154 * });
155 * // callback is optional
156 * q.push({name: 'bar'});
157 *
158 * // add some items to the queue (batch-wise)
159 * q.push([{name: 'baz'},{name: 'bay'},{name: 'bax'}], function(err) {
160 *     console.log('finished processing item');
161 * });
162 *
163 * // add some items to the front of the queue
164 * q.unshift({name: 'bar'}, function (err) {
165 *     console.log('finished processing bar');
166 * });
167 */