|
|
- 'use strict';
-
- Object.defineProperty(exports, "__esModule", {
- value: true
- });
- exports.default = asyncify;
-
- var _isObject = require('lodash/isObject');
-
- var _isObject2 = _interopRequireDefault(_isObject);
-
- var _initialParams = require('./internal/initialParams');
-
- var _initialParams2 = _interopRequireDefault(_initialParams);
-
- var _setImmediate = require('./internal/setImmediate');
-
- var _setImmediate2 = _interopRequireDefault(_setImmediate);
-
- function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
-
- /**
- * Take a sync function and make it async, passing its return value to a
- * callback. This is useful for plugging sync functions into a waterfall,
- * series, or other async functions. Any arguments passed to the generated
- * function will be passed to the wrapped function (except for the final
- * callback argument). Errors thrown will be passed to the callback.
- *
- * If the function passed to `asyncify` returns a Promise, that promises's
- * resolved/rejected state will be used to call the callback, rather than simply
- * the synchronous return value.
- *
- * This also means you can asyncify ES2017 `async` functions.
- *
- * @name asyncify
- * @static
- * @memberOf module:Utils
- * @method
- * @alias wrapSync
- * @category Util
- * @param {Function} func - The synchronous function, or Promise-returning
- * function to convert to an {@link AsyncFunction}.
- * @returns {AsyncFunction} An asynchronous wrapper of the `func`. To be
- * invoked with `(args..., callback)`.
- * @example
- *
- * // passing a regular synchronous function
- * async.waterfall([
- * async.apply(fs.readFile, filename, "utf8"),
- * async.asyncify(JSON.parse),
- * function (data, next) {
- * // data is the result of parsing the text.
- * // If there was a parsing error, it would have been caught.
- * }
- * ], callback);
- *
- * // passing a function returning a promise
- * async.waterfall([
- * async.apply(fs.readFile, filename, "utf8"),
- * async.asyncify(function (contents) {
- * return db.model.create(contents);
- * }),
- * function (model, next) {
- * // `model` is the instantiated model object.
- * // If there was an error, this function would be skipped.
- * }
- * ], callback);
- *
- * // es2017 example, though `asyncify` is not needed if your JS environment
- * // supports async functions out of the box
- * var q = async.queue(async.asyncify(async function(file) {
- * var intermediateStep = await processFile(file);
- * return await somePromise(intermediateStep)
- * }));
- *
- * q.push(files);
- */
- function asyncify(func) {
- return (0, _initialParams2.default)(function (args, callback) {
- var result;
- try {
- result = func.apply(this, args);
- } catch (e) {
- return callback(e);
- }
- // if result is Promise object
- if ((0, _isObject2.default)(result) && typeof result.then === 'function') {
- result.then(function (value) {
- invokeCallback(callback, null, value);
- }, function (err) {
- invokeCallback(callback, err.message ? err : new Error(err));
- });
- } else {
- callback(null, result);
- }
- });
- }
-
- function invokeCallback(callback, error, value) {
- try {
- callback(error, value);
- } catch (e) {
- (0, _setImmediate2.default)(rethrow, e);
- }
- }
-
- function rethrow(error) {
- throw error;
- }
- module.exports = exports['default'];
|