mapValues.js
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'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'];