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50 lines
1.5 KiB
50 lines
1.5 KiB
/** @license MIT License (c) copyright 2011-2013 original author or authors */ |
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/** |
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* pipeline.js |
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* |
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* Run a set of task functions in sequence, passing the result |
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* of the previous as an argument to the next. Like a shell |
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* pipeline, e.g. `cat file.txt | grep 'foo' | sed -e 's/foo/bar/g' |
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* |
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* @author Brian Cavalier |
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* @author John Hann |
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*/ |
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(function(define) { |
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define(function(require) { |
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var when = require('./when'); |
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var all = when.Promise.all; |
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var slice = Array.prototype.slice; |
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/** |
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* Run array of tasks in a pipeline where the next |
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* tasks receives the result of the previous. The first task |
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* will receive the initialArgs as its argument list. |
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* @param tasks {Array|Promise} array or promise for array of task functions |
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* @param [initialArgs...] {*} arguments to be passed to the first task |
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* @return {Promise} promise for return value of the final task |
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*/ |
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return function pipeline(tasks /* initialArgs... */) { |
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// Self-optimizing function to run first task with multiple |
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// args using apply, but subsequence tasks via direct invocation |
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var runTask = function(args, task) { |
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runTask = function(arg, task) { |
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return task(arg); |
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}; |
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return task.apply(null, args); |
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}; |
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return all(slice.call(arguments, 1)).then(function(args) { |
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return when.reduce(tasks, function(arg, task) { |
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return runTask(arg, task); |
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}, args); |
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}); |
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}; |
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}); |
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})(typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(require); }); |
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