Ruby's String Utils: center, rjust, ljust in JS

RubyUtils.js

/*
 * Ruby's String#center, String#rjust, String#ljust
 * 
 * https://jsfiddle.net/6v0bpffm/
 */

function ljust( string, width, padding ) {
	padding = padding || " ";
	padding = padding.substr( 0, 1 );
	if ( string.length < width )
		return string + padding.repeat( width - string.length );
	else
		return string;
}

function rjust( string, width, padding ) {
	padding = padding || " ";
	padding = padding.substr( 0, 1 );
	if ( string.length < width )
		return padding.repeat( width - string.length ) + string;
	else
		return string;
}

function center( string, width, padding ) {
	padding = padding || " ";
	padding = padding.substr( 0, 1 );
	if ( string.length < width ) {
		var len		= width - string.length;
		var remain	= ( len % 2 == 0 ) ? "" : padding;
		var pads	= padding.repeat( parseInt( len / 2 ) );
		return pads + string + pads + remain;
	}
	else
		return string;
}
 
console.log( center( "Ruby" , 10 ) );      // "   Ruby   "
console.log( rjust( "Ruby", 10 ) );       // "      Ruby"
console.log( ljust( "Ruby", 10 ) );       // "Ruby      "
console.log( center( "Ruby", 10, "+" ) ); // "+++Ruby+++"