A library to make errors.
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:
javascript
function(message, data)
You'll typically do something like:
javascript
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:
javascript
er instanceof UnknownFileTypeError
er instanceof Error
There is support for simple string substitutions like:
javascript
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.'.
You can create simple hierarchies as well using the prototype chain:
javascript
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:
javascript
er instanceof ChildError
er instanceof ParentError
er instanceof Error