custom-error

Create custom errors that inherit Error.

why

Extending Error is a real pain. This library deals with the quirks, providing a clean API to extend Error that works across JS environments, including Node and browsers.

api

customError(name, [ParentError])

Returns a new subclass of Error, or of ParentError if it is provided.

name

Required
Type: string

The display name of this class's errors. For example, the builtin TypeError class's name is "TypeError". This affects how the error is displayed when it is thrown.

ParentError

Type: Error, Error descendant
Default: Error

The Error type to be subclassed.

examples

var customError = require('custom-error');

var ApocalypseError = customError('ApocalypseError');

ApocalypseError() instanceof Error           // true
ApocalypseError() instanceof ApocalypseError // true

var UnixApocalypseError = customError('UnixApocalypseError', ApocalypseError)

UnixApocalypseError() instanceof Error                 // true
UnixApocalypseError() instanceof ApocalypseError       // true
UnixApocalypseError() instanceof UnixApocalypseError   // true

if (new Date().getFullYear() === 2038) {
  throw UnixApocalypseError('OH NOES')
}

using prototype

UnixApocalypseError.prototype.year = 2038

try {
  throw UnixApocalypseError()
}
catch (err) {
  console.log(err.year) // 2038
}

installation

npm install custom-error

license

MIT