Package Exports

makeerror

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (makeerror) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

makeerror

A library to make errors.

Basics

Makes an Error constructor function with the signature below. All arguments are optional, and if the first argument is not a String, it will be assumed to be data:

function(message, data)

You'll typically do something like:

var makeError = require('makeerror')
var UnknownFileTypeError = makeError(
  'UnknownFileTypeError',
  'The specified type is not known.'
)
var er = UnknownFileTypeError()

er will have a prototype chain that ensures:

er instanceof UnknownFileTypeError
er instanceof Error

Templatized Error Messages

There is support for simple string substitutions like:

var makeError = require('makeerror')
var UnknownFileTypeError = makeError(
  'UnknownFileTypeError',
  'The specified type "{type}" is not known.'
)
var er = UnknownFileTypeError({ type: 'bmp' })

Now er.message or er.toString() will return 'The specified type "bmp" is not known.'.

Prototype Hierarchies

You can create simple hierarchies as well using the prototype chain:

var makeError = require('makeerror')
var ParentError = makeError('ParentError')
var ChildError = makeError(
  'ChildError',
  'The child error.',
  { proto: ParentError() }
)
var er = ChildError()

er will have a prototype chain that ensures:

er instanceof ChildError
er instanceof ParentError
er instanceof Error