identifierfy

identifierfy

Rewrites an identifier string so its valid according to ES2015. Tested with Node.js 0.10 and above.

Please see this awesome article by Mathias Bynens for background.

Installation

npm install --save identifierfy

Usage

The module has one default export, the identifierfy function:

var identifierfy = require('identifierfy')

Call identifierfy() with an identifier string. It'll return a string that can be used as an identifier, which is useful when writing Babel plugins.

Characters that are not allowed in identifiers are dropped. Any character that follows a removed character is uppercased, except if the dropped character was at the front of the string.

If necessary the resulting identifier is prefixed with an underscore. This will happen if the string is a reserved word or if the first character cannot be used as the first character (but is fine as the second character).

Note that null is returned if all characters from the original string are dropped.

Examples

Input	Resulting identifier	Reason
'class	'_class'	Reserved word
'42'	'_42'	Identifiers cannot start with a number
'-foo'	'foo'	The - is dropped, but since it's as the front f is not uppercased
'foo-bar🙊baz'	'fooBarBaz'	The - and 🙊 characters are dropped, and the following characters uppercased
'foo-9'	foo9	9 can't be uppercased of course 😉
'💩'	null	Sadly emojis cannot be used as identifiers 😢