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Diffstat (limited to 'docs/v3/reduce.js.html')
-rw-r--r-- | docs/v3/reduce.js.html | 88 |
1 files changed, 82 insertions, 6 deletions
diff --git a/docs/v3/reduce.js.html b/docs/v3/reduce.js.html index e85a14e..c0c3d9e 100644 --- a/docs/v3/reduce.js.html +++ b/docs/v3/reduce.js.html @@ -112,14 +112,90 @@ import awaitify from './internal/awaitify' * @returns {Promise} a promise, if no callback is passed * @example * - * async.reduce([1,2,3], 0, function(memo, item, callback) { - * // pointless async: - * process.nextTick(function() { - * callback(null, memo + item) + * // 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); * }); - * }, function(err, result) { - * // result is now equal to the last value of memo, which is 6 + * } + * + * // 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 = once(callback); |