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Diffstat (limited to 'node_modules/async/autoInject.js')
| -rw-r--r-- | node_modules/async/autoInject.js | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/node_modules/async/autoInject.js b/node_modules/async/autoInject.js new file mode 100644 index 0000000..393baad --- /dev/null +++ b/node_modules/async/autoInject.js @@ -0,0 +1,182 @@ +'use strict'; + +Object.defineProperty(exports, "__esModule", { + value: true +}); +exports.default = autoInject; + +var _auto = require('./auto.js'); + +var _auto2 = _interopRequireDefault(_auto); + +var _wrapAsync = require('./internal/wrapAsync.js'); + +var _wrapAsync2 = _interopRequireDefault(_wrapAsync); + +function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } + +var FN_ARGS = /^(?:async\s+)?(?:function)?\s*\w*\s*\(\s*([^)]+)\s*\)(?:\s*{)/; +var ARROW_FN_ARGS = /^(?:async\s+)?\(?\s*([^)=]+)\s*\)?(?:\s*=>)/; +var FN_ARG_SPLIT = /,/; +var FN_ARG = /(=.+)?(\s*)$/; + +function stripComments(string) { + let stripped = ''; + let index = 0; + let endBlockComment = string.indexOf('*/'); + while (index < string.length) { + if (string[index] === '/' && string[index + 1] === '/') { + // inline comment + let endIndex = string.indexOf('\n', index); + index = endIndex === -1 ? string.length : endIndex; + } else if (endBlockComment !== -1 && string[index] === '/' && string[index + 1] === '*') { + // block comment + let endIndex = string.indexOf('*/', index); + if (endIndex !== -1) { + index = endIndex + 2; + endBlockComment = string.indexOf('*/', index); + } else { + stripped += string[index]; + index++; + } + } else { + stripped += string[index]; + index++; + } + } + return stripped; +} + +function parseParams(func) { + const src = stripComments(func.toString()); + let match = src.match(FN_ARGS); + if (!match) { + match = src.match(ARROW_FN_ARGS); + } + if (!match) throw new Error('could not parse args in autoInject\nSource:\n' + src); + let [, args] = match; + return args.replace(/\s/g, '').split(FN_ARG_SPLIT).map(arg => arg.replace(FN_ARG, '').trim()); +} + +/** + * A dependency-injected version of the [async.auto]{@link module:ControlFlow.auto} function. Dependent + * tasks are specified as parameters to the function, after the usual callback + * parameter, with the parameter names matching the names of the tasks it + * depends on. This can provide even more readable task graphs which can be + * easier to maintain. + * + * If a final callback is specified, the task results are similarly injected, + * specified as named parameters after the initial error parameter. + * + * The autoInject function is purely syntactic sugar and its semantics are + * otherwise equivalent to [async.auto]{@link module:ControlFlow.auto}. + * + * @name autoInject + * @static + * @memberOf module:ControlFlow + * @method + * @see [async.auto]{@link module:ControlFlow.auto} + * @category Control Flow + * @param {Object} tasks - An object, each of whose properties is an {@link AsyncFunction} of + * the form 'func([dependencies...], callback). The object's key of a property + * serves as the name of the task defined by that property, i.e. can be used + * when specifying requirements for other tasks. + * * The `callback` parameter is a `callback(err, result)` which must be called + * when finished, passing an `error` (which can be `null`) and the result of + * the function's execution. The remaining parameters name other tasks on + * which the task is dependent, and the results from those tasks are the + * arguments of those parameters. + * @param {Function} [callback] - An optional callback which is called when all + * the tasks have been completed. It receives the `err` argument if any `tasks` + * pass an error to their callback, and a `results` object with any completed + * task results, similar to `auto`. + * @returns {Promise} a promise, if no callback is passed + * @example + * + * // The example from `auto` can be rewritten as follows: + * async.autoInject({ + * get_data: function(callback) { + * // async code to get some data + * callback(null, 'data', 'converted to array'); + * }, + * make_folder: function(callback) { + * // async code to create a directory to store a file in + * // this is run at the same time as getting the data + * callback(null, 'folder'); + * }, + * write_file: function(get_data, make_folder, callback) { + * // once there is some data and the directory exists, + * // write the data to a file in the directory + * callback(null, 'filename'); + * }, + * email_link: function(write_file, callback) { + * // once the file is written let's email a link to it... + * // write_file contains the filename returned by write_file. + * callback(null, {'file':write_file, 'email':'user@example.com'}); + * } + * }, function(err, results) { + * console.log('err = ', err); + * console.log('email_link = ', results.email_link); + * }); + * + * // If you are using a JS minifier that mangles parameter names, `autoInject` + * // will not work with plain functions, since the parameter names will be + * // collapsed to a single letter identifier. To work around this, you can + * // explicitly specify the names of the parameters your task function needs + * // in an array, similar to Angular.js dependency injection. + * + * // This still has an advantage over plain `auto`, since the results a task + * // depends on are still spread into arguments. + * async.autoInject({ + * //... + * write_file: ['get_data', 'make_folder', function(get_data, make_folder, callback) { + * callback(null, 'filename'); + * }], + * email_link: ['write_file', function(write_file, callback) { + * callback(null, {'file':write_file, 'email':'user@example.com'}); + * }] + * //... + * }, function(err, results) { + * console.log('err = ', err); + * console.log('email_link = ', results.email_link); + * }); + */ +function autoInject(tasks, callback) { + var newTasks = {}; + + Object.keys(tasks).forEach(key => { + var taskFn = tasks[key]; + var params; + var fnIsAsync = (0, _wrapAsync.isAsync)(taskFn); + var hasNoDeps = !fnIsAsync && taskFn.length === 1 || fnIsAsync && taskFn.length === 0; + + if (Array.isArray(taskFn)) { + params = [...taskFn]; + taskFn = params.pop(); + + newTasks[key] = params.concat(params.length > 0 ? newTask : taskFn); + } else if (hasNoDeps) { + // no dependencies, use the function as-is + newTasks[key] = taskFn; + } else { + params = parseParams(taskFn); + if (taskFn.length === 0 && !fnIsAsync && params.length === 0) { + throw new Error("autoInject task functions require explicit parameters."); + } + + // remove callback param + if (!fnIsAsync) params.pop(); + + newTasks[key] = params.concat(newTask); + } + + function newTask(results, taskCb) { + var newArgs = params.map(name => results[name]); + newArgs.push(taskCb); + (0, _wrapAsync2.default)(taskFn)(...newArgs); + } + }); + + return (0, _auto2.default)(newTasks, callback); +} +module.exports = exports['default'];
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