code: function size(collection) {
        var length = collection ? collection.length : 0;
        return (typeof length == 'number' && length > -1 && length <= maxSafeInteger)
          ? length
          : keys(collection).length;
      }
docs: Gets the size of the collection by returning `collection.length` for arrays
  and array-like objects or the number of own enumerable properties for objects.
  
  @static
  @memberOf _
  @category Collections
  @param {Array|Object|string} collection The collection to inspect.
  @returns {number} Returns `collection.length` or number of own enumerable properties.
  @example
  
  _.size([1, 2]);
  // => 2
  
  _.size({ 'one': 1, 'two': 2, 'three': 3 });
  // => 3
  
  _.size('pebbles');
  // => 7