flatten_array.js

function flatten_array(arr) {
  var i;

  for (i=0; i<arr.length; ) {
    if (Object.prototype.toString.call(arr[i]) == "[object Array]") {
      // prepend `splice()` arguments to `tmp` array, to enable `apply()` call
      arr.splice.apply(arr,[i,1].concat(arr[i]));
      continue;
    }
    i++;
  }

  return arr;
}

flatten_array([1,2,[3,[4,5],[],6,[[[7]]]]]); // [1,2,3,4,5,6,7]

// no recursion
function flatten_array(arr) {
  var i, tmp;

  for (i=0; i<arr.length; ) {
    if (arr[i] instanceof Array) {
      // prepend `splice()` arguments to `tmp` array, to enable `apply()` call
      arr.splice.apply(arr,[i,1].concat(arr[i]));
      continue;
    }
    i++;
  }

  return arr;
}

flatten_array([1,2,[3,[4,5],[],6,[[[7]]]]]); // [1,2,3,4,5,6,7]

@notmasteryet

nice idea, but i don't think it works fully correctly (doesn't handle nested deep i don't think?). try this input:

flatten_array([[[],[1,2]],[[[3]]]]); // should get: [1,2,3], instead: [[],1,2,[[3]]]

my version doesn't work with that input either. still trying to debug it.

i fixed it, i think.

@getify, mine is working for any level of nesting :)

.. did you copy only portion of the code?

sorry, must have missed something, seems to work. thanks! updating my snippet now accordingly.