| 'use strict'; |
| |
| Object.defineProperty(exports, "__esModule", { |
| value: true |
| }); |
| |
| exports.default = function (worker, concurrency) { |
| var _worker = (0, _wrapAsync2.default)(worker); |
| return (0, _queue2.default)(function (items, cb) { |
| _worker(items[0], cb); |
| }, concurrency, 1); |
| }; |
| |
| var _queue = require('./internal/queue'); |
| |
| var _queue2 = _interopRequireDefault(_queue); |
| |
| var _wrapAsync = require('./internal/wrapAsync'); |
| |
| var _wrapAsync2 = _interopRequireDefault(_wrapAsync); |
| |
| 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} remove - remove items from the queue that match a test |
| * function. The test function will be passed an object with a `data` property, |
| * and a `priority` property, if this is a |
| * [priorityQueue]{@link module:ControlFlow.priorityQueue} object. |
| * Invoked with `queue.remove(testFn)`, where `testFn` is of the form |
| * `function ({data, priority}) {}` and returns a Boolean. |
| * @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. No more tasks |
| * should be pushed to the queue after calling this function. 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 {AsyncFunction} worker - An async function for processing a queued task. |
| * 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'); |
| * }); |
| */ |