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author | Ram Goli <ramsgoli@gmail.com> | 2017-12-12 23:46:25 +0000 |
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committer | Anatoli Papirovski <apapirovski@mac.com> | 2017-12-17 13:19:03 -0500 |
commit | 3db136a74a34d610a0bea26f7da46ea2f33d96db (patch) | |
tree | b68b2cb2b99b989e4bb020a21113794c42f0caca /doc | |
parent | efffcc262c77a58ad3c75787497df46863d1b7a6 (diff) | |
download | android-node-v8-3db136a74a34d610a0bea26f7da46ea2f33d96db.tar.gz android-node-v8-3db136a74a34d610a0bea26f7da46ea2f33d96db.tar.bz2 android-node-v8-3db136a74a34d610a0bea26f7da46ea2f33d96db.zip |
doc: change "Node.js style cb" to "error-first cb"
Change the awkward "Node.js style callback" phrasing to the more
informative "error-first callback."
PR-URL: https://github.com/nodejs/node/pull/17638
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/api/errors.md | 21 | ||||
-rw-r--r-- | doc/api/util.md | 17 |
2 files changed, 20 insertions, 18 deletions
diff --git a/doc/api/errors.md b/doc/api/errors.md index fab75e9bc4..776639d2e4 100644 --- a/doc/api/errors.md +++ b/doc/api/errors.md @@ -128,21 +128,22 @@ they are thrown *after* the calling code has already exited. Developers must refer to the documentation for each method to determine exactly how errors raised by those methods are propagated. -### Node.js style callbacks +### Error-first callbacks <!--type=misc--> Most asynchronous methods exposed by the Node.js core API follow an idiomatic -pattern referred to as a "Node.js style callback". With this pattern, a -callback function is passed to the method as an argument. When the operation -either completes or an error is raised, the callback function is called with -the Error object (if any) passed as the first argument. If no error was raised, -the first argument will be passed as `null`. +pattern referred to as an _error-first callback_ (sometimes referred to as +a _Node.js style callback_). With this pattern, a callback function is passed +to the method as an argument. When the operation either completes or an error +is raised, the callback function is called with +the Error object (if any) passed as the first argument. If no error was +raised, the first argument will be passed as `null`. ```js const fs = require('fs'); -function nodeStyleCallback(err, data) { +function errorFirstCallback(err, data) { if (err) { console.error('There was an error', err); return; @@ -150,13 +151,13 @@ function nodeStyleCallback(err, data) { console.log(data); } -fs.readFile('/some/file/that/does-not-exist', nodeStyleCallback); -fs.readFile('/some/file/that/does-exist', nodeStyleCallback); +fs.readFile('/some/file/that/does-not-exist', errorFirstCallback); +fs.readFile('/some/file/that/does-exist', errorFirstCallback); ``` The JavaScript `try / catch` mechanism **cannot** be used to intercept errors generated by asynchronous APIs. A common mistake for beginners is to try to -use `throw` inside a Node.js style callback: +use `throw` inside an error-first callback: ```js // THIS WILL NOT WORK: diff --git a/doc/api/util.md b/doc/api/util.md index 1e72954126..c653802d3d 100644 --- a/doc/api/util.md +++ b/doc/api/util.md @@ -21,9 +21,10 @@ added: v8.2.0 * Returns: {Function} a callback style function Takes an `async` function (or a function that returns a Promise) and returns a -function following the Node.js error first callback style. In the callback, the -first argument will be the rejection reason (or `null` if the Promise resolved), -and the second argument will be the resolved value. +function following the error-first callback style, i.e. taking +a `(err, value) => ...` callback as the last argument. In the callback, the +first argument will be the rejection reason (or `null` if the Promise +resolved), and the second argument will be the resolved value. For example: @@ -530,8 +531,8 @@ added: v8.0.0 * `original` {Function} * Returns: {Function} -Takes a function following the common Node.js callback style, i.e. taking a -`(err, value) => ...` callback as the last argument, and returns a version +Takes a function following the common error-first callback style, i.e. taking +a `(err, value) => ...` callback as the last argument, and returns a version that returns promises. For example: @@ -567,9 +568,9 @@ will return its value, see [Custom promisified functions][]. `promisify()` assumes that `original` is a function taking a callback as its final argument in all cases. If `original` is not a function, `promisify()` -will throw an error. If `original` is a function but its last argument is not a -Node.js style callback, it will still be passed a Node.js style callback -as its last argument. +will throw an error. If `original` is a function but its last argument is not +an error-first callback, it will still be passed an error-first +callback as its last argument. ### Custom promisified functions |