130 lines
5.7 KiB
JavaScript
130 lines
5.7 KiB
JavaScript
'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');
|
|
* });
|
|
*/ |