Code to flatten array

flatten.js

var array = [[1,2,[3,4]],4]; 

function flattenArray(array){
	
    var length = array.length;

    var flattenedArray = new Array();
    
    for(var x = 0; x < length; x++){
      
        if( Array.isArray(array[x]) && array[x].length > 1){
            for (var j = 0; j <  array[x].length; ++j){
                flattenedArray.push(array[x][j]);
            }
        }else{
            console.log("not array " + array[x]);
            flattenedArray.push(array[x]);
        }

    }

   return flattenedArray;
}