从多维数组中删除未定义

Question

So I need to remove empty (undefined) items from the multidimensional array. Atm my code looks like this (it's a method I run so that's why i am using this :

f: function(arr) {
    var __ = this;
    arr = arr.filter(function(item) {
        return Array.isArray(item) ? __.f(item) : typeof(item) !== "undefined";
    });
return arr;
}

but if i run console.log(myObject.f([1, 2, , , , , 3, 4, [5, , , , , ], 6, , , , 8, 3, [[[], 9]]])); i get [ 1, 2, 3, 4, [ 5, , , , ], 6, 8, 3, [ [ [], 9 ] ] ] and that is kinda weird result. I goes pretty well for the first layer but removes only one undefined from inner layers. Also I would like to remove a subarray that consists of no items.

Answer 1

How about something like this:

var arr = [1, 2, , , , , 3, 4, [5, , , , , ], 6, , , , 8, 3, [[[], 9]]];

var remove = function (array) {
  var result = [];

  array.forEach(function (item) {
    if (Array.isArray(item) && item.length!=0) {
      // Item is a nested array, go one level deeper recursively
      result.push(remove(item));
    }
    else if (typeof item !== 'undefined') {
      result.push(item);
    }
  });

  return result;
};

And then console.log(remove(arr)); gives us [1, 2, 3, 4, [5], 6, 8, 3, [[[], 9]]]

Answer 2

Use reductions people! They are beautiful!

function stripUndefined (arr) {
  return arr.reduce(function (result, item) {
    result.push( Array.isArray(item) && !item.length ? stripUndefined(item) : item );
    return result;
  }, []);
}

Answer 3

Similar to Gilad's answer, but completely skipping arrays that result in an empty array (eg [,,,,,] )

function cleanArray2d(array){
  var result = [];

  array.forEach(function (item) {
    if (Array.isArray(item) && item.length!=0) {
      // Item is a nested array, go one level deeper recursively

      var nestedArray = cleanArray2d(item);
      if (nestedArray.length > 0)
        result.push(cleanArray2d(item));
    }
    else if (typeof item !== 'undefined' && item != "") {
      result.push(item);
    }
  });

  return result;
}