4.4 Array Flattener created by smillaraaq - https://repl.it/GzQT/1

4.4 Array Flattener.js

function flatten(argArray){
  var newArray=[];
  for(i=0;i<argArray.length;i++){
    if(typeof argArray[i]==="object"){
      for(x=0;x<argArray[i].length;x++){
        newArray.push(argArray[i][x]);
      }
    }else{
      newArray.push(argArray[i]);
    }
  }
  console.log(newArray);
}

flatten([1,[2,3],4]);