MACHIN

32/node_modules/async/inject.js

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+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+
+var _eachOfSeries = require('./eachOfSeries.js');
+
+var _eachOfSeries2 = _interopRequireDefault(_eachOfSeries);
+
+var _once = require('./internal/once.js');
+
+var _once2 = _interopRequireDefault(_once);
+
+var _wrapAsync = require('./internal/wrapAsync.js');
+
+var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
+
+var _awaitify = require('./internal/awaitify.js');
+
+var _awaitify2 = _interopRequireDefault(_awaitify);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/**
+ * Reduces `coll` into a single value using an async `iteratee` to return each
+ * successive step. `memo` is the initial state of the reduction. This function
+ * only operates in series.
+ *
+ * For performance reasons, it may make sense to split a call to this function
+ * into a parallel map, and then use the normal `Array.prototype.reduce` on the
+ * results. This function is for situations where each step in the reduction
+ * needs to be async; if you can get the data before reducing it, then it's
+ * probably a good idea to do so.
+ *
+ * @name reduce
+ * @static
+ * @memberOf module:Collections
+ * @method
+ * @alias inject
+ * @alias foldl
+ * @category Collection
+ * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
+ * @param {*} memo - The initial state of the reduction.
+ * @param {AsyncFunction} iteratee - A function applied to each item in the
+ * array to produce the next step in the reduction.
+ * The `iteratee` should complete with the next state of the reduction.
+ * If the iteratee completes with an error, the reduction is stopped and the
+ * main `callback` is immediately called with the error.
+ * Invoked with (memo, item, callback).
+ * @param {Function} [callback] - A callback which is called after all the
+ * `iteratee` functions have finished. Result is the reduced value. Invoked with
+ * (err, result).
+ * @returns {Promise} a promise, if no callback is passed
+ * @example
+ *
+ * // file1.txt is a file that is 1000 bytes in size
+ * // file2.txt is a file that is 2000 bytes in size
+ * // file3.txt is a file that is 3000 bytes in size
+ * // file4.txt does not exist
+ *
+ * const fileList = ['file1.txt','file2.txt','file3.txt'];
+ * const withMissingFileList = ['file1.txt','file2.txt','file3.txt', 'file4.txt'];
+ *
+ * // asynchronous function that computes the file size in bytes
+ * // file size is added to the memoized value, then returned
+ * function getFileSizeInBytes(memo, file, callback) {
+ *     fs.stat(file, function(err, stat) {
+ *         if (err) {
+ *             return callback(err);
+ *         }
+ *         callback(null, memo + stat.size);
+ *     });
+ * }
+ *
+ * // Using callbacks
+ * async.reduce(fileList, 0, getFileSizeInBytes, function(err, result) {
+ *     if (err) {
+ *         console.log(err);
+ *     } else {
+ *         console.log(result);
+ *         // 6000
+ *         // which is the sum of the file sizes of the three files
+ *     }
+ * });
+ *
+ * // Error Handling
+ * async.reduce(withMissingFileList, 0, getFileSizeInBytes, function(err, result) {
+ *     if (err) {
+ *         console.log(err);
+ *         // [ Error: ENOENT: no such file or directory ]
+ *     } else {
+ *         console.log(result);
+ *     }
+ * });
+ *
+ * // Using Promises
+ * async.reduce(fileList, 0, getFileSizeInBytes)
+ * .then( result => {
+ *     console.log(result);
+ *     // 6000
+ *     // which is the sum of the file sizes of the three files
+ * }).catch( err => {
+ *     console.log(err);
+ * });
+ *
+ * // Error Handling
+ * async.reduce(withMissingFileList, 0, getFileSizeInBytes)
+ * .then( result => {
+ *     console.log(result);
+ * }).catch( err => {
+ *     console.log(err);
+ *     // [ Error: ENOENT: no such file or directory ]
+ * });
+ *
+ * // Using async/await
+ * async () => {
+ *     try {
+ *         let result = await async.reduce(fileList, 0, getFileSizeInBytes);
+ *         console.log(result);
+ *         // 6000
+ *         // which is the sum of the file sizes of the three files
+ *     }
+ *     catch (err) {
+ *         console.log(err);
+ *     }
+ * }
+ *
+ * // Error Handling
+ * async () => {
+ *     try {
+ *         let result = await async.reduce(withMissingFileList, 0, getFileSizeInBytes);
+ *         console.log(result);
+ *     }
+ *     catch (err) {
+ *         console.log(err);
+ *         // [ Error: ENOENT: no such file or directory ]
+ *     }
+ * }
+ *
+ */
+function reduce(coll, memo, iteratee, callback) {
+    callback = (0, _once2.default)(callback);
+    var _iteratee = (0, _wrapAsync2.default)(iteratee);
+    return (0, _eachOfSeries2.default)(coll, (x, i, iterCb) => {
+        _iteratee(memo, x, (err, v) => {
+            memo = v;
+            iterCb(err);
+        });
+    }, err => callback(err, memo));
+}
+exports.default = (0, _awaitify2.default)(reduce, 4);
+module.exports = exports['default'];