HORIZON PROJECT

'use strict';

Object.defineProperty(exports, "__esModule", {

  value: true

});

exports.default = cargo;

var _queue = require('./internal/queue');

var _queue2 = _interopRequireDefault(_queue);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**

 * A cargo of tasks for the worker function to complete. Cargo inherits all of

 * the same methods and event callbacks as [`queue`]{@link module:ControlFlow.queue}.

 * @typedef {Object} CargoObject

 * @memberOf module:ControlFlow

 * @property {Function} length - A function returning the number of items

 * waiting to be processed. Invoke like `cargo.length()`.

 * @property {number} payload - An `integer` for determining how many tasks

 * should be process per round. This property can be changed after a `cargo` is

 * created to alter the payload on-the-fly.

 * @property {Function} push - Adds `task` to the `queue`. The callback is

 * called once the `worker` has finished processing the task. Instead of a

 * single task, an array of `tasks` can be submitted. The respective callback is

 * used for every task in the list. Invoke like `cargo.push(task, [callback])`.

 * @property {Function} saturated - A callback that is called when the

 * `queue.length()` hits the concurrency and further tasks will be queued.

 * @property {Function} empty - A callback that is called when the last item

 * from the `queue` is given to a `worker`.

 * @property {Function} drain - A callback that is called when the last item

 * from the `queue` has returned from the `worker`.

 * @property {Function} idle - a function returning false if there are items

 * waiting or being processed, or true if not. Invoke like `cargo.idle()`.

 * @property {Function} pause - a function that pauses the processing of tasks

 * until `resume()` is called. Invoke like `cargo.pause()`.

 * @property {Function} resume - a function that resumes the processing of

 * queued tasks when the queue is paused. Invoke like `cargo.resume()`.

 * @property {Function} kill - a function that removes the `drain` callback and

 * empties remaining tasks from the queue forcing it to go idle. Invoke like `cargo.kill()`.

 */

/**

 * Creates a `cargo` object with the specified payload. Tasks added to the

 * cargo will be processed altogether (up to the `payload` limit). If the

 * `worker` is in progress, the task is queued until it becomes available. Once

 * the `worker` has completed some tasks, each callback of those tasks is

 * called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)

 * for how `cargo` and `queue` work.

 *

 * While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers

 * at a time, cargo passes an array of tasks to a single worker, repeating

 * when the worker is finished.

 *

 * @name cargo

 * @static

 * @memberOf module:ControlFlow

 * @method

 * @see [async.queue]{@link module:ControlFlow.queue}

 * @category Control Flow

 * @param {Function} worker - An asynchronous function for processing an array

 * of queued tasks, which must call its `callback(err)` argument when finished,

 * with an optional `err` argument. Invoked with `(tasks, callback)`.

 * @param {number} [payload=Infinity] - An optional `integer` for determining

 * how many tasks should be processed per round; if omitted, the default is

 * unlimited.

 * @returns {module:ControlFlow.CargoObject} A cargo object to manage the tasks. Callbacks can

 * attached as certain properties to listen for specific events during the

 * lifecycle of the cargo and inner queue.

 * @example

 *

 * // create a cargo object with payload 2

 * var cargo = async.cargo(function(tasks, callback) {

 *     for (var i=0; i<tasks.length; i++) {

 *         console.log('hello ' + tasks[i].name);

 *     }

 *     callback();

 * }, 2);

 *

 * // add some items

 * cargo.push({name: 'foo'}, function(err) {

 *     console.log('finished processing foo');

 * });

 * cargo.push({name: 'bar'}, function(err) {

 *     console.log('finished processing bar');

 * });

 * cargo.push({name: 'baz'}, function(err) {

 *     console.log('finished processing baz');

 * });

 */

function cargo(worker, payload) {

  return (0, _queue2.default)(worker, 1, payload);

}

module.exports = exports['default'];