JavaScript function for flattening an array.

JavaScript flatten

var flatten = function( array ) {
  var flattenedArray = [ ];
  var flattenLoop = function( i ) { i.forEach( function( j ) {
      if ( Object.prototype.toString.call( j ) === '[object Array]' ) {
        flattenLoop( j );
      } else {
        flattenedArray.push( j );
      }
    });
  };
  flattenLoop( array );
  return flattenedArray;
};