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94 lines
4.5 KiB
94 lines
4.5 KiB
'use strict';
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.default = cargo;
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var _queue = require('./internal/queue');
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var _queue2 = _interopRequireDefault(_queue);
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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/**
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* A cargo of tasks for the worker function to complete. Cargo inherits all of
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* the same methods and event callbacks as [`queue`]{@link module:ControlFlow.queue}.
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* @typedef {Object} CargoObject
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* @memberOf module:ControlFlow
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* @property {Function} length - A function returning the number of items
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* waiting to be processed. Invoke like `cargo.length()`.
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* @property {number} payload - An `integer` for determining how many tasks
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* should be process per round. This property can be changed after a `cargo` is
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* created to alter the payload on-the-fly.
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* @property {Function} push - Adds `task` to the `queue`. The callback is
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* called once the `worker` has finished processing the task. Instead of a
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* single task, an array of `tasks` can be submitted. The respective callback is
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* used for every task in the list. Invoke like `cargo.push(task, [callback])`.
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* @property {Function} saturated - A callback that is called when the
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* `queue.length()` hits the concurrency and further tasks will be queued.
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* @property {Function} empty - A callback that is called when the last item
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* from the `queue` is given to a `worker`.
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* @property {Function} drain - A callback that is called when the last item
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* from the `queue` has returned from the `worker`.
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* @property {Function} idle - a function returning false if there are items
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* waiting or being processed, or true if not. Invoke like `cargo.idle()`.
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* @property {Function} pause - a function that pauses the processing of tasks
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* until `resume()` is called. Invoke like `cargo.pause()`.
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* @property {Function} resume - a function that resumes the processing of
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* queued tasks when the queue is paused. Invoke like `cargo.resume()`.
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* @property {Function} kill - a function that removes the `drain` callback and
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* empties remaining tasks from the queue forcing it to go idle. Invoke like `cargo.kill()`.
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*/
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/**
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* Creates a `cargo` object with the specified payload. Tasks added to the
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* cargo will be processed altogether (up to the `payload` limit). If the
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* `worker` is in progress, the task is queued until it becomes available. Once
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* the `worker` has completed some tasks, each callback of those tasks is
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* called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)
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* for how `cargo` and `queue` work.
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*
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* While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers
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* at a time, cargo passes an array of tasks to a single worker, repeating
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* when the worker is finished.
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*
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* @name cargo
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* @static
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* @memberOf module:ControlFlow
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* @method
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* @see [async.queue]{@link module:ControlFlow.queue}
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* @category Control Flow
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* @param {AsyncFunction} worker - An asynchronous function for processing an array
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* of queued tasks. Invoked with `(tasks, callback)`.
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* @param {number} [payload=Infinity] - An optional `integer` for determining
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* how many tasks should be processed per round; if omitted, the default is
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* unlimited.
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* @returns {module:ControlFlow.CargoObject} A cargo object to manage the tasks. Callbacks can
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* attached as certain properties to listen for specific events during the
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* lifecycle of the cargo and inner queue.
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* @example
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*
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* // create a cargo object with payload 2
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* var cargo = async.cargo(function(tasks, callback) {
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* for (var i=0; i<tasks.length; i++) {
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* console.log('hello ' + tasks[i].name);
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* }
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* callback();
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* }, 2);
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*
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* // add some items
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* cargo.push({name: 'foo'}, function(err) {
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* console.log('finished processing foo');
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* });
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* cargo.push({name: 'bar'}, function(err) {
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* console.log('finished processing bar');
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* });
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* cargo.push({name: 'baz'}, function(err) {
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* console.log('finished processing baz');
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* });
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*/
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function cargo(worker, payload) {
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return (0, _queue2.default)(worker, 1, payload);
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}
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module.exports = exports['default'];
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