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Extensible string utility for converting, identifying and flipping string case

Case: An extensible utility to convert, identify, and flip string case.

Download: Case.min.js or Case.js Build Status
Bower: bower install Case (note the big 'C')
NPM: npm install case (little 'c' due to NPM restrictions)
Component: component install nbubna/Case


Each of the following functions will first "undo" previous case manipulations before applying the desired case to the given string.

Case.upper('foo_bar')                       -> 'FOO BAR'
Case.lower('fooBar')                        -> 'foo bar'
Case.snake('Foo bar!')                      -> 'foo_bar'
Case.pascal('')                      -> 'FooBar'
Case.camel('foo, bar')                      -> 'fooBar'
Case.kebab('Foo? Bar.')                     -> 'foo-bar'
Case.constant('Foo-Bar')                    -> 'FOO_BAR'
Case.title('foo v. bar')                    -> 'Foo v. Bar''foo_v_bar')                   -> 'Foo V Bar'
Case.sentence('"foo!" said bar', ['Bar'])   -> '"Foo!" said Bar'

sentence(str, names) accepts an array of proper names that should be capitalized, regardless of location in the sentence. This function is specialized, but useful when dealing with input generated with capslock on (i.e. everything my grandma types).

There are four additional functions:

  • of(str): identifies the case of a string, returns undefined if it doesn't match a known type
  • flip(str): reverses the case of letters, no other changes
  • random(str): randomizes the case of letters, no other changes
  • type(name, fn): extends Case with a new case type
Case.of('foo')          -> 'lower'
Case.of('foo_bar')      -> 'snake'
Case.of('Foo v Bar')    -> 'title'
Case.of('foo_ Bar')     -> undefined
Case.flip('FlipMe')     -> 'fLIPmE'
Case.flip('TEST THIS!') -> 'test this!'
Case.random('Hello!')   -> 'hElLO!'
Case.type('bang', function(s) {
    return Case.upper(s, '!')+'!';
Case.bang('bang')       -> 'BANG!'
Case.of('TEST!THIS!')   -> 'bang'

Registering functions via type() means Case.of supports them automatically.

Oh, did you notice that little Case.upper(s, '!')? Yeah, upper() and lower() accept a second "fill" argument that will replace any characters which are not letters or numbers. It's handy, sometimes. :)

Release History

  • 2013-06-10 v1.0.0 (public, initial)
  • 2013-06-20 v1.0.1 (regex improvements)
  • 2013-08-23 v1.0.3 (better support for Node, Component and AMD)
  • 2014-10-24 v1.1.2 (regexps used are now extensible and support more latin diacritics)
  • 2015-01-27 v1.2.0 (deprecate squish in favor of pascal)
  • 2015-01-28 v1.2.1 (fix UMD regression)
  • 2015-10-27 v1.3.0 (Case.kebab and Case.random)
  • 2015-12-02 v1.3.2 (fix title case when small word is first or last)
  • 2016-02-01 v1.3.3 (Case.of('foo') to return lower, not snake)
  • 2016-02-07 v1.4.0 (fix apostrophe handling)
  • 2016-02-08 v1.4.1 (fix swallowed prefix/suffix on lone words)
  • 2016-11-11 v1.4.2 (add typings for TypeScript support)