Dbqb_Study/吴光慧学习笔记/11.1/study/node_modules/async/mapValues.js

'use strict';

Object.defineProperty(exports, "__esModule", {
    value: true
});
exports.default = mapValues;

var _mapValuesLimit = require('./mapValuesLimit.js');

var _mapValuesLimit2 = _interopRequireDefault(_mapValuesLimit);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * A relative of [`map`]{@link module:Collections.map}, designed for use with objects.
 *
 * Produces a new Object by mapping each value of `obj` through the `iteratee`
 * function. The `iteratee` is called each `value` and `key` from `obj` and a
 * callback for when it has finished processing. Each of these callbacks takes
 * two arguments: an `error`, and the transformed item from `obj`. If `iteratee`
 * passes an error to its callback, the main `callback` (for the `mapValues`
 * function) is immediately called with the error.
 *
 * Note, the order of the keys in the result is not guaranteed.  The keys will
 * be roughly in the order they complete, (but this is very engine-specific)
 *
 * @name mapValues
 * @static
 * @memberOf module:Collections
 * @method
 * @category Collection
 * @param {Object} obj - A collection to iterate over.
 * @param {AsyncFunction} iteratee - A function to apply to each value and key
 * in `coll`.
 * The iteratee should complete with the transformed value as its result.
 * Invoked with (value, key, callback).
 * @param {Function} [callback] - A callback which is called when all `iteratee`
 * functions have finished, or an error occurs. `result` is a new object consisting
 * of each key from `obj`, with each transformed value on the right-hand side.
 * 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 fileMap = {
 *     f1: 'file1.txt',
 *     f2: 'file2.txt',
 *     f3: 'file3.txt'
 * };
 *
 * const withMissingFileMap = {
 *     f1: 'file1.txt',
 *     f2: 'file2.txt',
 *     f3: 'file4.txt'
 * };
 *
 * // asynchronous function that returns the file size in bytes
 * function getFileSizeInBytes(file, key, callback) {
 *     fs.stat(file, function(err, stat) {
 *         if (err) {
 *             return callback(err);
 *         }
 *         callback(null, stat.size);
 *     });
 * }
 *
 * // Using callbacks
 * async.mapValues(fileMap, getFileSizeInBytes, function(err, result) {
 *     if (err) {
 *         console.log(err);
 *     } else {
 *         console.log(result);
 *         // result is now a map of file size in bytes for each file, e.g.
 *         // {
 *         //     f1: 1000,
 *         //     f2: 2000,
 *         //     f3: 3000
 *         // }
 *     }
 * });
 *
 * // Error handling
 * async.mapValues(withMissingFileMap, getFileSizeInBytes, function(err, result) {
 *     if (err) {
 *         console.log(err);
 *         // [ Error: ENOENT: no such file or directory ]
 *     } else {
 *         console.log(result);
 *     }
 * });
 *
 * // Using Promises
 * async.mapValues(fileMap, getFileSizeInBytes)
 * .then( result => {
 *     console.log(result);
 *     // result is now a map of file size in bytes for each file, e.g.
 *     // {
 *     //     f1: 1000,
 *     //     f2: 2000,
 *     //     f3: 3000
 *     // }
 * }).catch (err => {
 *     console.log(err);
 * });
 *
 * // Error Handling
 * async.mapValues(withMissingFileMap, 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.mapValues(fileMap, getFileSizeInBytes);
 *         console.log(result);
 *         // result is now a map of file size in bytes for each file, e.g.
 *         // {
 *         //     f1: 1000,
 *         //     f2: 2000,
 *         //     f3: 3000
 *         // }
 *     }
 *     catch (err) {
 *         console.log(err);
 *     }
 * }
 *
 * // Error Handling
 * async () => {
 *     try {
 *         let result = await async.mapValues(withMissingFileMap, getFileSizeInBytes);
 *         console.log(result);
 *     }
 *     catch (err) {
 *         console.log(err);
 *         // [ Error: ENOENT: no such file or directory ]
 *     }
 * }
 *
 */
function mapValues(obj, iteratee, callback) {
    return (0, _mapValuesLimit2.default)(obj, Infinity, iteratee, callback);
}
module.exports = exports.default;