'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 {AsyncFunction} worker - An asynchronous function for processing an array
   * of queued tasks. 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'];