diff options
Diffstat (limited to 'lib/map.js')
-rw-r--r-- | lib/map.js | 84 |
1 files changed, 82 insertions, 2 deletions
@@ -35,9 +35,89 @@ import awaitify from './internal/awaitify' * @returns {Promise} a promise, if no callback is passed * @example * - * async.map(['file1','file2','file3'], fs.stat, function(err, results) { - * // results is now an array of stats for each file + * // 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','file4.txt']; + * + * // asynchronous function that returns the file size in bytes + * function getFileSizeInBytes(file, callback) { + * fs.stat(file, function(err, stat) { + * if (err) { + * return callback(err); + * } + * callback(null, stat.size); + * }); + * } + * + * // Using callbacks + * async.map(fileList, getFileSizeInBytes, function(err, results) { + * if (err) { + * console.log(err); + * } else { + * console.log(results); + * // results is now an array of the file size in bytes for each file, e.g. + * // [ 1000, 2000, 3000] + * } + * }); + * + * // Error Handling + * async.map(withMissingFileList, getFileSizeInBytes, function(err, results) { + * if (err) { + * console.log(err); + * // [ Error: ENOENT: no such file or directory ] + * } else { + * console.log(results); + * } + * }); + * + * // Using Promises + * async.map(fileList, getFileSizeInBytes) + * .then( results => { + * console.log(results); + * // results is now an array of the file size in bytes for each file, e.g. + * // [ 1000, 2000, 3000] + * }).catch( err => { + * console.log(err); + * }); + * + * // Error Handling + * async.map(withMissingFileList, getFileSizeInBytes) + * .then( results => { + * console.log(results); + * }).catch( err => { + * console.log(err); + * // [ Error: ENOENT: no such file or directory ] * }); + * + * // Using async/await + * async () => { + * try { + * let results = await async.map(fileList, getFileSizeInBytes); + * console.log(results); + * // results is now an array of the file size in bytes for each file, e.g. + * // [ 1000, 2000, 3000] + * } + * catch (err) { + * console.log(err); + * } + * } + * + * // Error Handling + * async () => { + * try { + * let results = await async.map(withMissingFileList, getFileSizeInBytes); + * console.log(results); + * } + * catch (err) { + * console.log(err); + * // [ Error: ENOENT: no such file or directory ] + * } + * } + * */ function map (coll, iteratee, callback) { return _map(eachOf, coll, iteratee, callback) |