function camelcase( str ) {
	if ( !isString( str ) ) {
		throw new TypeError( format( 'invalid argument. First argument must be a string. Value: `%s`.', str ) );
	}
	return base( str );
}
Converts a string to camel case.

@param {string} str - string to convert
@throws {TypeError} must provide a string
@returns {string} camel-cased string

@example
var out = camelcase( 'foo bar' );
// returns 'fooBar'

@example
var out = camelcase( 'IS_MOBILE' );
// returns 'isMobile'

@example
var out = camelcase( 'Hello World!' );
// returns 'helloWorld'

@example
var out = camelcase( '--foo-bar--' );
// returns 'fooBar'