https://github.com/luochen1990/node-define-error
Define pretty printed, nested custom errors easily
https://github.com/luochen1990/node-define-error
Last synced: 12 months ago
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Define pretty printed, nested custom errors easily
- Host: GitHub
- URL: https://github.com/luochen1990/node-define-error
- Owner: luochen1990
- License: mit
- Created: 2018-01-19T16:16:18.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2019-01-09T07:36:22.000Z (over 7 years ago)
- Last Synced: 2025-07-03T05:04:03.662Z (12 months ago)
- Language: CoffeeScript
- Size: 7.81 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
Node Define Error
=================
Define pretty printed, nested custom errors easily.
Features
--------
- define custom error easily
- define custom fields for your error
- pretty printed error message
- nested error support
- brief stack trace for nested error
Install
-------
```
npm install node-define-error
```
Simple Usage
------------
```
defineError = require('node-define-error')
MyError = defineError('MyError')
throw new MyError('a simple custom error')
```
Advanced Usage
--------------
File `rpc-error.js`:
```javascript
defineError = require('node-define-error')
RpcError = defineError('RpcError', ['from', 'api']) //NOTE: define custom fields here as specification
fetch = (url) => Promise.reject(new Error('failed to fetch "' + url + '"'))
rpcCall = async () => {
try {
const response = await fetch('http://path/to/some/api')
const result = JSON.parse(response)
if (result.success !== true) {
throw new RpcError({from: 'server', 'api': 'path/to/some/api'})
}
return result
} catch (err) {
throw new RpcError({from: 'client', 'api': 'path/to/some/api'}, err) //NOTE: pass on an error as a cause of this error, this is optional
}
}
rpcCall().catch((e) => {
console.log(e.stack)
})
```
Error stack:
```text
RpcError:
[from]: "client"
[api]: "path/to/some/api"
Caused By: Error: failed to fetch "http://path/to/some/api"
at fetch (/the/very/very/long/path/to/rpc-error.js:5:33)
at rpcCall (/the/very/very/long/path/to/rpc-error.js:16:15)
at
at runMicrotasksCallback (internal/process/next_tick.js:121:5)
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickCallback (internal/process/next_tick.js:180:9)
at Function.Module.runMain (module.js:678:11)
at startup (bootstrap_node.js:187:16)
at bootstrap_node.js:608:3
```
Deep Nested Example
-------------------
File `nested-error.js`:
```javascript
const defineError = require('node-define-error')
const MyAdvError = defineError('MyAdvError', ['f', 'msg'])
function f0() {
throw new Error('the inner custom error')
}
function f1() {
try {
return f0()
} catch (e) {
throw new MyAdvError({ f: 'f1', msg: 'the medium custom error' }, e)
}
}
function f2() {
try {
return f1()
} catch (e) {
throw new MyAdvError({ f: 'f2', msg: 'the outer custom error' }, e)
}
}
f2()
```
Error stack:
```text
MyAdvError:
[f]: "f2"
[msg]: "the outer custom error"
Caused By: MyAdvError:
[f]: "f1"
[msg]: "the medium custom error"
Caused By: Error: the inner custom error
at f0 (/the/very/very/long/path/to/nested-error.js:6:11)
at f1 (/the/very/very/long/path/to/nested-error.js:13:15)
at f2 (/the/very/very/long/path/to/nested-error.js:21:15)
at Object. (/the/very/very/long/path/to/nested-error.js:25:1)
at Module._compile (module.js:635:30)
at Object.Module._extensions..js (module.js:646:10)
at Module.load (module.js:554:32)
at tryModuleLoad (module.js:497:12)
at Function.Module._load (module.js:489:3)
at Function.Module.runMain (module.js:676:10)
at startup (bootstrap_node.js:187:16)
at bootstrap_node.js:608:3
```
Reference
---------
- [Tero's answer @stackoverflow](http://stackoverflow.com/questions/1382107/whats-a-good-way-to-extend-error-in-javascript/5251506#5251506)
- [Onur Yıldırım's answer @stackoverflow](https://stackoverflow.com/a/35881508/1608276)
- [customizing-stack-traces @v8-wiki](https://github.com/v8/v8/wiki/Stack-Trace-API#customizing-stack-traces)