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							289 lines
						
					
					
						
							9.6 KiB
						
					
					
				'use strict'; | 
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 | 
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Object.defineProperty(exports, "__esModule", { | 
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    value: true | 
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}); | 
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 | 
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exports.default = function (tasks, concurrency, callback) { | 
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    if (typeof concurrency === 'function') { | 
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        // concurrency is optional, shift the args. | 
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        callback = concurrency; | 
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        concurrency = null; | 
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    } | 
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    callback = (0, _once2.default)(callback || _noop2.default); | 
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    var keys = (0, _keys2.default)(tasks); | 
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    var numTasks = keys.length; | 
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    if (!numTasks) { | 
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        return callback(null); | 
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    } | 
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    if (!concurrency) { | 
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        concurrency = numTasks; | 
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    } | 
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 | 
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    var results = {}; | 
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    var runningTasks = 0; | 
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    var hasError = false; | 
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 | 
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    var listeners = Object.create(null); | 
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 | 
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    var readyTasks = []; | 
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 | 
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    // for cycle detection: | 
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    var readyToCheck = []; // tasks that have been identified as reachable | 
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    // without the possibility of returning to an ancestor task | 
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    var uncheckedDependencies = {}; | 
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 | 
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    (0, _baseForOwn2.default)(tasks, function (task, key) { | 
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        if (!(0, _isArray2.default)(task)) { | 
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            // no dependencies | 
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            enqueueTask(key, [task]); | 
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            readyToCheck.push(key); | 
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            return; | 
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        } | 
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 | 
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        var dependencies = task.slice(0, task.length - 1); | 
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        var remainingDependencies = dependencies.length; | 
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        if (remainingDependencies === 0) { | 
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            enqueueTask(key, task); | 
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            readyToCheck.push(key); | 
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            return; | 
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        } | 
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        uncheckedDependencies[key] = remainingDependencies; | 
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 | 
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        (0, _arrayEach2.default)(dependencies, function (dependencyName) { | 
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            if (!tasks[dependencyName]) { | 
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                throw new Error('async.auto task `' + key + '` has a non-existent dependency `' + dependencyName + '` in ' + dependencies.join(', ')); | 
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            } | 
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            addListener(dependencyName, function () { | 
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                remainingDependencies--; | 
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                if (remainingDependencies === 0) { | 
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                    enqueueTask(key, task); | 
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                } | 
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            }); | 
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        }); | 
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    }); | 
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 | 
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    checkForDeadlocks(); | 
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    processQueue(); | 
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 | 
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    function enqueueTask(key, task) { | 
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        readyTasks.push(function () { | 
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            runTask(key, task); | 
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        }); | 
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    } | 
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 | 
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    function processQueue() { | 
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        if (readyTasks.length === 0 && runningTasks === 0) { | 
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            return callback(null, results); | 
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        } | 
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        while (readyTasks.length && runningTasks < concurrency) { | 
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            var run = readyTasks.shift(); | 
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            run(); | 
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        } | 
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    } | 
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 | 
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    function addListener(taskName, fn) { | 
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        var taskListeners = listeners[taskName]; | 
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        if (!taskListeners) { | 
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            taskListeners = listeners[taskName] = []; | 
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        } | 
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 | 
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        taskListeners.push(fn); | 
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    } | 
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 | 
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    function taskComplete(taskName) { | 
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        var taskListeners = listeners[taskName] || []; | 
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        (0, _arrayEach2.default)(taskListeners, function (fn) { | 
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            fn(); | 
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        }); | 
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        processQueue(); | 
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    } | 
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 | 
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    function runTask(key, task) { | 
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        if (hasError) return; | 
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 | 
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        var taskCallback = (0, _onlyOnce2.default)(function (err, result) { | 
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            runningTasks--; | 
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            if (arguments.length > 2) { | 
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                result = (0, _slice2.default)(arguments, 1); | 
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            } | 
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            if (err) { | 
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                var safeResults = {}; | 
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                (0, _baseForOwn2.default)(results, function (val, rkey) { | 
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                    safeResults[rkey] = val; | 
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                }); | 
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                safeResults[key] = result; | 
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                hasError = true; | 
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                listeners = Object.create(null); | 
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 | 
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                callback(err, safeResults); | 
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            } else { | 
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                results[key] = result; | 
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                taskComplete(key); | 
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            } | 
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        }); | 
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 | 
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        runningTasks++; | 
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        var taskFn = (0, _wrapAsync2.default)(task[task.length - 1]); | 
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        if (task.length > 1) { | 
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            taskFn(results, taskCallback); | 
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        } else { | 
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            taskFn(taskCallback); | 
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        } | 
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    } | 
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 | 
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    function checkForDeadlocks() { | 
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        // Kahn's algorithm | 
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        // https://en.wikipedia.org/wiki/Topological_sorting#Kahn.27s_algorithm | 
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        // http://connalle.blogspot.com/2013/10/topological-sortingkahn-algorithm.html | 
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        var currentTask; | 
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        var counter = 0; | 
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        while (readyToCheck.length) { | 
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            currentTask = readyToCheck.pop(); | 
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            counter++; | 
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            (0, _arrayEach2.default)(getDependents(currentTask), function (dependent) { | 
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                if (--uncheckedDependencies[dependent] === 0) { | 
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                    readyToCheck.push(dependent); | 
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                } | 
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            }); | 
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        } | 
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 | 
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        if (counter !== numTasks) { | 
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            throw new Error('async.auto cannot execute tasks due to a recursive dependency'); | 
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        } | 
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    } | 
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 | 
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    function getDependents(taskName) { | 
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        var result = []; | 
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        (0, _baseForOwn2.default)(tasks, function (task, key) { | 
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            if ((0, _isArray2.default)(task) && (0, _baseIndexOf2.default)(task, taskName, 0) >= 0) { | 
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                result.push(key); | 
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            } | 
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        }); | 
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        return result; | 
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    } | 
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}; | 
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 | 
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var _arrayEach = require('lodash/_arrayEach'); | 
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 | 
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var _arrayEach2 = _interopRequireDefault(_arrayEach); | 
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 | 
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var _baseForOwn = require('lodash/_baseForOwn'); | 
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 | 
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var _baseForOwn2 = _interopRequireDefault(_baseForOwn); | 
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 | 
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var _baseIndexOf = require('lodash/_baseIndexOf'); | 
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 | 
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var _baseIndexOf2 = _interopRequireDefault(_baseIndexOf); | 
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 | 
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var _isArray = require('lodash/isArray'); | 
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 | 
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var _isArray2 = _interopRequireDefault(_isArray); | 
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 | 
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var _keys = require('lodash/keys'); | 
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 | 
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var _keys2 = _interopRequireDefault(_keys); | 
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 | 
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var _noop = require('lodash/noop'); | 
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 | 
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var _noop2 = _interopRequireDefault(_noop); | 
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 | 
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var _slice = require('./internal/slice'); | 
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 | 
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var _slice2 = _interopRequireDefault(_slice); | 
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 | 
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var _once = require('./internal/once'); | 
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 | 
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var _once2 = _interopRequireDefault(_once); | 
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 | 
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var _onlyOnce = require('./internal/onlyOnce'); | 
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 | 
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var _onlyOnce2 = _interopRequireDefault(_onlyOnce); | 
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 | 
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var _wrapAsync = require('./internal/wrapAsync'); | 
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 | 
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var _wrapAsync2 = _interopRequireDefault(_wrapAsync); | 
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 | 
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } | 
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 | 
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module.exports = exports['default']; | 
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 | 
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/** | 
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 * Determines the best order for running the {@link AsyncFunction}s in `tasks`, based on | 
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 * their requirements. Each function can optionally depend on other functions | 
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 * being completed first, and each function is run as soon as its requirements | 
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 * are satisfied. | 
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 * | 
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 * If any of the {@link AsyncFunction}s pass an error to their callback, the `auto` sequence | 
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 * will stop. Further tasks will not execute (so any other functions depending | 
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 * on it will not run), and the main `callback` is immediately called with the | 
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 * error. | 
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 * | 
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 * {@link AsyncFunction}s also receive an object containing the results of functions which | 
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 * have completed so far as the first argument, if they have dependencies. If a | 
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 * task function has no dependencies, it will only be passed a callback. | 
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 * | 
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 * @name auto | 
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 * @static | 
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 * @memberOf module:ControlFlow | 
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 * @method | 
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 * @category Control Flow | 
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 * @param {Object} tasks - An object. Each of its properties is either a | 
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 * function or an array of requirements, with the {@link AsyncFunction} itself the last item | 
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 * in the array. The object's key of a property serves as the name of the task | 
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 * defined by that property, i.e. can be used when specifying requirements for | 
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 * other tasks. The function receives one or two arguments: | 
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 * * a `results` object, containing the results of the previously executed | 
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 *   functions, only passed if the task has any dependencies, | 
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 * * a `callback(err, result)` function, which must be called when finished, | 
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 *   passing an `error` (which can be `null`) and the result of the function's | 
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 *   execution. | 
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 * @param {number} [concurrency=Infinity] - An optional `integer` for | 
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 * determining the maximum number of tasks that can be run in parallel. By | 
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 * default, as many as possible. | 
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 * @param {Function} [callback] - An optional callback which is called when all | 
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 * the tasks have been completed. It receives the `err` argument if any `tasks` | 
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 * pass an error to their callback. Results are always returned; however, if an | 
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 * error occurs, no further `tasks` will be performed, and the results object | 
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 * will only contain partial results. Invoked with (err, results). | 
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 * @returns undefined | 
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 * @example | 
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 * | 
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 * async.auto({ | 
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 *     // this function will just be passed a callback | 
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 *     readData: async.apply(fs.readFile, 'data.txt', 'utf-8'), | 
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 *     showData: ['readData', function(results, cb) { | 
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 *         // results.readData is the file's contents | 
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 *         // ... | 
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 *     }] | 
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 * }, callback); | 
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 * | 
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 * async.auto({ | 
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 *     get_data: function(callback) { | 
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 *         console.log('in get_data'); | 
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 *         // async code to get some data | 
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 *         callback(null, 'data', 'converted to array'); | 
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 *     }, | 
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 *     make_folder: function(callback) { | 
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 *         console.log('in make_folder'); | 
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 *         // async code to create a directory to store a file in | 
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 *         // this is run at the same time as getting the data | 
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 *         callback(null, 'folder'); | 
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 *     }, | 
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 *     write_file: ['get_data', 'make_folder', function(results, callback) { | 
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 *         console.log('in write_file', JSON.stringify(results)); | 
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 *         // once there is some data and the directory exists, | 
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 *         // write the data to a file in the directory | 
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 *         callback(null, 'filename'); | 
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 *     }], | 
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 *     email_link: ['write_file', function(results, callback) { | 
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 *         console.log('in email_link', JSON.stringify(results)); | 
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 *         // once the file is written let's email a link to it... | 
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 *         // results.write_file contains the filename returned by write_file. | 
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 *         callback(null, {'file':results.write_file, 'email':'user@example.com'}); | 
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 *     }] | 
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 * }, function(err, results) { | 
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 *     console.log('err = ', err); | 
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 *     console.log('results = ', results); | 
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 * }); | 
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 */ |