HORIZON PROJECT

'use strict';

Object.defineProperty(exports, "__esModule", {

  value: true

});

exports.default = function (worker, concurrency) {

  return (0, _queue2.default)(function (items, cb) {

    worker(items[0], cb);

  }, concurrency, 1);

};

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

var _queue2 = _interopRequireDefault(_queue);

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

module.exports = exports['default'];

/**

 * A queue of tasks for the worker function to complete.

 * @typedef {Object} QueueObject

 * @memberOf module:ControlFlow

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

 * waiting to be processed. Invoke with `queue.length()`.

 * @property {boolean} started - a boolean indicating whether or not any

 * items have been pushed and processed by the queue.

 * @property {Function} running - a function returning the number of items

 * currently being processed. Invoke with `queue.running()`.

 * @property {Function} workersList - a function returning the array of items

 * currently being processed. Invoke with `queue.workersList()`.

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

 * waiting or being processed, or true if not. Invoke with `queue.idle()`.

 * @property {number} concurrency - an integer for determining how many `worker`

 * functions should be run in parallel. This property can be changed after a

 * `queue` is created to alter the concurrency on-the-fly.

 * @property {Function} push - add a new task to the `queue`. Calls `callback`

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

 * a `tasks` array can be submitted. The respective callback is used for every

 * task in the list. Invoke with `queue.push(task, [callback])`,

 * @property {Function} unshift - add a new task to the front of the `queue`.

 * Invoke with `queue.unshift(task, [callback])`.

 * @property {Function} saturated - a callback that is called when the number of

 * running workers hits the `concurrency` limit, and further tasks will be

 * queued.

 * @property {Function} unsaturated - a callback that is called when the number

 * of running workers is less than the `concurrency` & `buffer` limits, and

 * further tasks will not be queued.

 * @property {number} buffer - A minimum threshold buffer in order to say that

 * the `queue` is `unsaturated`.

 * @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} error - a callback that is called when a task errors.

 * Has the signature `function(error, task)`.

 * @property {boolean} paused - a boolean for determining whether the queue is

 * in a paused state.

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

 * until `resume()` is called. Invoke with `queue.pause()`.

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

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

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

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

 */

/**

 * Creates a `queue` object with the specified `concurrency`. Tasks added to the

 * `queue` are processed in parallel (up to the `concurrency` limit). If all

 * `worker`s are in progress, the task is queued until one becomes available.

 * Once a `worker` completes a `task`, that `task`'s callback is called.

 *

 * @name queue

 * @static

 * @memberOf module:ControlFlow

 * @method

 * @category Control Flow

 * @param {Function} worker - An asynchronous function for processing a queued

 * task, which must call its `callback(err)` argument when finished, with an

 * optional `error` as an argument.  If you want to handle errors from an

 * individual task, pass a callback to `q.push()`. Invoked with

 * (task, callback).

 * @param {number} [concurrency=1] - An `integer` for determining how many

 * `worker` functions should be run in parallel.  If omitted, the concurrency

 * defaults to `1`.  If the concurrency is `0`, an error is thrown.

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

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

 * lifecycle of the queue.

 * @example

 *

 * // create a queue object with concurrency 2

 * var q = async.queue(function(task, callback) {

 *     console.log('hello ' + task.name);

 *     callback();

 * }, 2);

 *

 * // assign a callback

 * q.drain = function() {

 *     console.log('all items have been processed');

 * };

 *

 * // add some items to the queue

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

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

 * });

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

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

 * });

 *

 * // add some items to the queue (batch-wise)

 * q.push([{name: 'baz'},{name: 'bay'},{name: 'bax'}], function(err) {

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

 * });

 *

 * // add some items to the front of the queue

 * q.unshift({name: 'bar'}, function (err) {

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

 * });

 */