Is there an easy way to make nested array flat?

Question

That is to make this:

[ [\'dog\',\'cat\', [\'chicken\', \'bear\'] ],[\'mouse\',\'horse\'] ]

into:

[\'dog\',\'cat\',\'chicken\',\'

Answer 1

In modern browsers you can do this without any external libraries in a few lines:

Array.prototype.flatten = function() {
  return this.reduce(function(prev, cur) {
    var more = [].concat(cur).some(Array.isArray);
    return prev.concat(more ? cur.flatten() : cur);
  },[]);
};

console.log([['dog','cat',['chicken', 'bear']],['mouse','horse']].flatten());
//^ ["dog", "cat", "chicken", "bear", "mouse", "horse"]