docs: function anagram( str, x ) {
  	if ( !isString( str ) ) {
  		throw new TypeError( 'anagram()::invalid input argument. First argument must be a string. Value: `' + str + '`.' );
  	}
  	if ( !isString( x ) ) {
  		return false;
  	}
  	str = str.toLowerCase()
  		.replace( /[^a-z0-9]/g, '' );
  	x = x.toLowerCase()
  		.replace( /[^a-z0-9]/g, '' );
  	if ( str.length !== x.length ) {
  		return false;
  	}
  	str = str.split( '' )
  		.sort( ascending )
  		.join( '' );
  	x = x.split( '' )
  		.sort( ascending )
  		.join( '' );
  	return ( str === x );
  }