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

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

Build Status npm version npm


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''foo_v_bar') -> 'Foo V Bar'

Code Helpers

Case.snake('Foo bar!')   -> 'foo_bar'
Case.pascal('')   -> 'FooBar'
Case.camel('foo, bar')   -> 'fooBar'
Case.kebab('Foo? Bar.')  -> 'foo-bar'
Case.header('fooBar=')   -> 'Foo-Bar'
Case.constant('Foo-Bar') -> 'FOO_BAR'

UI Helpers

Case.title('foo v. bar')                    -> 'Foo v. Bar'
Case.sentence('"foo!" said bar', ['Bar'])   -> '"Foo!" said Bar'

Case.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).

Custom Casing

Case.lower('FOO-BAR', '.')                  -> ''
Case.upper('Foo? Bar.', '__')               -> 'FOO__BAR''fooBar', ' + ')               -> 'Foo + Bar'
Case.lower("Don't keep 'em!", "/", true)    -> 'dont/keep/em'"'ello, world.", null, true)   -> 'Ello, World.'

Case.upper, Case.lower, and accept an optional "fill" value that will replace any characters which are not letters and numbers. All three also accept a third optional boolean argument indicating if apostrophes are to be stripped out or left in. For example, programmatic case changes (snake, kebab, pascal, camel, constant) are best without apostrophes, but user-facing ones (title, sentence) do not want "don't" turned into "Dont".

Extending Case

Case.type('bang', function(s) {
    return Case.upper(s, '!')+'!';
Case.bang('bang')       -> 'BANG!'
Case.of('TEST!THIS!')   -> 'bang'

Case.type(name, fn): extends Case, creating a new function on Case and adding Case.of support automatically.


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.of(str): identifies the case of a string, returns undefined if it doesn't match a known type
  • Case.flip(str): reverses the case of letters, no other changes
  • Case.random(str): randomizes the case of letters, no other changes

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)
  • 2017-03-09 v1.5.0 (add Header-Case and expose noApostrophes option for upper/lower/capital fns)