https://github.com/pfrazee/zerr

custom js error construction
https://github.com/pfrazee/zerr

Last synced: 11 days ago
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custom js error construction

• Host: GitHub
• URL: https://github.com/pfrazee/zerr
• Owner: pfrazee
• Created: 2015-09-13T18:14:03.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2016-02-07T21:48:47.000Z (almost 9 years ago)
• Last Synced: 2024-12-12T08:51:35.434Z (17 days ago)
• Language: JavaScript
• Size: 5.86 KB
• Stars: 4
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# ZErr

Custom JS error creator that subclasses `Error`, sets `.name` `.stack` and `.message`, and provides simple interpolation to construct error messages.

```js

var zerr = require('zerr')

// first param: error name

// second param: string template for error messages (substitutes '%' with args in constructor)

var BadParam = zerr('BadParam', '% is an invalid parameter. Expected %.')

// using the created error:

try { throw new BadParam('x', 'y') }

catch (e) {

  console.log(e.name) // => 'BadParamError'

  console.log(e.message) // => 'x is an invalid parameter. Expected y.'

  console.log(e.stack) // => 'BadParamError: x is an invalid parameter. Expected y.\nat repl:1:13...'

  console.log(e instanceof Error) // => true

  console.log(e instanceof BadParam) // => true

}

// the `new` is optional

throw BadParam('x', 'y')

// if no string template is given, zerr will just use the constructor's param as the message

var BadParam = zerr('BadParam')

try { throw new BadParam('x is bad') }

catch (e) {

  console.log(e.message) // => 'x is bad'

}

// if you pass an error as the first param to the constructor, zerr will add its stack to the stack history

// this helps you follow the trail of an exception that is caught, and then rethrown

// (taken from https://github.com/dominictarr/explain-error)

try { throw new BadParam(new BadParam('earlier error'), 'later error') }

catch (e) {

  console.log(e.stack) /* =>

  BadPararmError: later error

      at repl:1:7

    BadPararmError: earlier error

      at repl:1:15

  */

}

```