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170 lines
6.3 KiB
170 lines
6.3 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 = autoInject; |
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var _auto = require('./auto'); |
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var _auto2 = _interopRequireDefault(_auto); |
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var _baseForOwn = require('lodash/_baseForOwn'); |
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var _baseForOwn2 = _interopRequireDefault(_baseForOwn); |
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var _arrayMap = require('lodash/_arrayMap'); |
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var _arrayMap2 = _interopRequireDefault(_arrayMap); |
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var _isArray = require('lodash/isArray'); |
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var _isArray2 = _interopRequireDefault(_isArray); |
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var _trim = require('lodash/trim'); |
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var _trim2 = _interopRequireDefault(_trim); |
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var _wrapAsync = require('./internal/wrapAsync'); |
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var _wrapAsync2 = _interopRequireDefault(_wrapAsync); |
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } |
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var FN_ARGS = /^(?:async\s+)?(function)?\s*[^\(]*\(\s*([^\)]*)\)/m; |
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var FN_ARG_SPLIT = /,/; |
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var FN_ARG = /(=.+)?(\s*)$/; |
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var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg; |
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function parseParams(func) { |
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func = func.toString().replace(STRIP_COMMENTS, ''); |
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func = func.match(FN_ARGS)[2].replace(' ', ''); |
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func = func ? func.split(FN_ARG_SPLIT) : []; |
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func = func.map(function (arg) { |
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return (0, _trim2.default)(arg.replace(FN_ARG, '')); |
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}); |
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return func; |
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} |
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/** |
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* A dependency-injected version of the [async.auto]{@link module:ControlFlow.auto} function. Dependent |
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* tasks are specified as parameters to the function, after the usual callback |
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* parameter, with the parameter names matching the names of the tasks it |
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* depends on. This can provide even more readable task graphs which can be |
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* easier to maintain. |
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* |
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* If a final callback is specified, the task results are similarly injected, |
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* specified as named parameters after the initial error parameter. |
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* |
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* The autoInject function is purely syntactic sugar and its semantics are |
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* otherwise equivalent to [async.auto]{@link module:ControlFlow.auto}. |
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* |
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* @name autoInject |
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* @static |
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* @memberOf module:ControlFlow |
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* @method |
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* @see [async.auto]{@link module:ControlFlow.auto} |
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* @category Control Flow |
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* @param {Object} tasks - An object, each of whose properties is an {@link AsyncFunction} of |
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* the form 'func([dependencies...], callback). The object's key of a property |
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* serves as the name of the task defined by that property, i.e. can be used |
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* when specifying requirements for other tasks. |
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* * The `callback` parameter is a `callback(err, result)` which must be called |
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* when finished, passing an `error` (which can be `null`) and the result of |
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* the function's execution. The remaining parameters name other tasks on |
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* which the task is dependent, and the results from those tasks are the |
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* arguments of those parameters. |
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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, and a `results` object with any completed |
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* task results, similar to `auto`. |
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* @example |
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* |
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* // The example from `auto` can be rewritten as follows: |
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* async.autoInject({ |
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* get_data: function(callback) { |
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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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* // 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: function(get_data, make_folder, callback) { |
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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: function(write_file, callback) { |
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* // once the file is written let's email a link to it... |
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* // write_file contains the filename returned by write_file. |
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* callback(null, {'file':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('email_link = ', results.email_link); |
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* }); |
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* |
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* // If you are using a JS minifier that mangles parameter names, `autoInject` |
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* // will not work with plain functions, since the parameter names will be |
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* // collapsed to a single letter identifier. To work around this, you can |
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* // explicitly specify the names of the parameters your task function needs |
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* // in an array, similar to Angular.js dependency injection. |
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* |
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* // This still has an advantage over plain `auto`, since the results a task |
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* // depends on are still spread into arguments. |
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* async.autoInject({ |
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* //... |
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* write_file: ['get_data', 'make_folder', function(get_data, make_folder, callback) { |
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* callback(null, 'filename'); |
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* }], |
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* email_link: ['write_file', function(write_file, callback) { |
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* callback(null, {'file':write_file, 'email':'user@example.com'}); |
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* }] |
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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('email_link = ', results.email_link); |
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* }); |
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*/ |
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function autoInject(tasks, callback) { |
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var newTasks = {}; |
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(0, _baseForOwn2.default)(tasks, function (taskFn, key) { |
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var params; |
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var fnIsAsync = (0, _wrapAsync.isAsync)(taskFn); |
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var hasNoDeps = !fnIsAsync && taskFn.length === 1 || fnIsAsync && taskFn.length === 0; |
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if ((0, _isArray2.default)(taskFn)) { |
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params = taskFn.slice(0, -1); |
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taskFn = taskFn[taskFn.length - 1]; |
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newTasks[key] = params.concat(params.length > 0 ? newTask : taskFn); |
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} else if (hasNoDeps) { |
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// no dependencies, use the function as-is |
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newTasks[key] = taskFn; |
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} else { |
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params = parseParams(taskFn); |
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if (taskFn.length === 0 && !fnIsAsync && params.length === 0) { |
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throw new Error("autoInject task functions require explicit parameters."); |
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} |
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// remove callback param |
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if (!fnIsAsync) params.pop(); |
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newTasks[key] = params.concat(newTask); |
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} |
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function newTask(results, taskCb) { |
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var newArgs = (0, _arrayMap2.default)(params, function (name) { |
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return results[name]; |
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}); |
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newArgs.push(taskCb); |
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(0, _wrapAsync2.default)(taskFn).apply(null, newArgs); |
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} |
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}); |
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(0, _auto2.default)(newTasks, callback); |
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} |
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module.exports = exports['default']; |