code: function takeWhile(array, predicate) {
          return array && array.length ? baseWhile(array, getIteratee(predicate, 3)) : [];
        }
docs: Creates a slice of `array` with elements taken from the beginning. Elements
  are taken until `predicate` returns falsey. The predicate is invoked with
  three arguments: (value, index, array).
  
  @static
  @memberOf _
  @category Array
  @param {Array} array The array to query.
  @param {Function|Object|string} [predicate=_.identity] The function invoked per iteration.
  @returns {Array} Returns the slice of `array`.
  @example
  
  var users = [
  { 'user': 'barney',  'active': false },
  { 'user': 'fred',    'active': false},
  { 'user': 'pebbles', 'active': true }
  ];
  
  _.takeWhile(users, function(o) { return !o.active; });
  // => objects for ['barney', 'fred']
  
  // The `_.matches` iteratee shorthand.
  _.takeWhile(users, { 'user': 'barney', 'active': false });
  // => objects for ['barney']
  
  // The `_.matchesProperty` iteratee shorthand.
  _.takeWhile(users, ['active', false]);
  // => objects for ['barney', 'fred']
  
  // The `_.property` iteratee shorthand.
  _.takeWhile(users, 'active');
  // => []