|
|
- # node-errno
-
- > Better [libuv](https://github.com/libuv/libuv)/[Node.js](https://nodejs.org)/[io.js](https://iojs.org) error handling & reporting. Available in npm as *errno*.
-
- [![npm](https://img.shields.io/npm/v/errno.svg)](https://www.npmjs.com/package/errno)
- [![Build Status](https://secure.travis-ci.org/rvagg/node-errno.png)](http://travis-ci.org/rvagg/node-errno)
- [![npm](https://img.shields.io/npm/dm/errno.svg)](https://www.npmjs.com/package/errno)
-
- * [errno exposed](#errnoexposed)
- * [Custom errors](#customerrors)
-
- <a name="errnoexposed"></a>
- ## errno exposed
-
- Ever find yourself needing more details about Node.js errors? Me too, so *node-errno* contains the errno mappings direct from libuv so you can use them in your code.
-
- **By errno:**
-
- ```js
- require('errno').errno[3]
- // → {
- // "errno": 3,
- // "code": "EACCES",
- // "description": "permission denied"
- // }
- ```
-
- **By code:**
-
- ```js
- require('errno').code.ENOTEMPTY
- // → {
- // "errno": 53,
- // "code": "ENOTEMPTY",
- // "description": "directory not empty"
- // }
- ```
-
- **Make your errors more descriptive:**
-
- ```js
- var errno = require('errno')
-
- function errmsg(err) {
- var str = 'Error: '
- // if it's a libuv error then get the description from errno
- if (errno.errno[err.errno])
- str += errno.errno[err.errno].description
- else
- str += err.message
-
- // if it's a `fs` error then it'll have a 'path' property
- if (err.path)
- str += ' [' + err.path + ']'
-
- return str
- }
-
- var fs = require('fs')
-
- fs.readFile('thisisnotarealfile.txt', function (err, data) {
- if (err)
- console.log(errmsg(err))
- })
- ```
-
- **Use as a command line tool:**
-
- ```
- ~ $ errno 53
- {
- "errno": 53,
- "code": "ENOTEMPTY",
- "description": "directory not empty"
- }
- ~ $ errno EROFS
- {
- "errno": 56,
- "code": "EROFS",
- "description": "read-only file system"
- }
- ~ $ errno foo
- No such errno/code: "foo"
- ```
-
- Supply no arguments for the full list. Error codes are processed case-insensitive.
-
- You will need to install with `npm install errno -g` if you want the `errno` command to be available without supplying a full path to the node_modules installation.
-
- <a name="customerrors"></a>
- ## Custom errors
-
- Use `errno.custom.createError()` to create custom `Error` objects to throw around in your Node.js library. Create error hierarchies so `instanceof` becomes a useful tool in tracking errors. Call-stack is correctly captured at the time you create an instance of the error object, plus a `cause` property will make available the original error object if you pass one in to the constructor.
-
- ```js
- var create = require('errno').custom.createError
- var MyError = create('MyError') // inherits from Error
- var SpecificError = create('SpecificError', MyError) // inherits from MyError
- var OtherError = create('OtherError', MyError)
-
- // use them!
- if (condition) throw new SpecificError('Eeek! Something bad happened')
-
- if (err) return callback(new OtherError(err))
- ```
-
- Also available is a `errno.custom.FilesystemError` with in-built access to errno properties:
-
- ```js
- fs.readFile('foo', function (err, data) {
- if (err) return callback(new errno.custom.FilesystemError(err))
- // do something else
- })
- ```
-
- The resulting error object passed through the callback will have the following properties: `code`, `errno`, `path` and `message` will contain a descriptive human-readable message.
-
- ## Contributors
-
- * [bahamas10](https://github.com/bahamas10) (Dave Eddy) - Added CLI
- * [ralphtheninja](https://github.com/ralphtheninja) (Lars-Magnus Skog)
-
- ## Copyright & Licence
-
- *Copyright (c) 2012-2015 [Rod Vagg](https://github.com/rvagg) ([@rvagg](https://twitter.com/rvagg))*
-
- Made available under the MIT licence:
-
- Permission is hereby granted, free of charge, to any person obtaining a copy
- of this software and associated documentation files (the "Software"), to deal
- in the Software without restriction, including without limitation the rights
- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- copies of the Software, and to permit persons to whom the Software is furnished
- to do so, subject to the following conditions:
-
- The above copyright notice and this permission notice shall be included in all
- copies or substantial portions of the Software.
-
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- SOFTWARE.
|