code: function addToContainer(container, key, val) {
    if (container instanceof Array) {
      container.push(val);
    } else if (container instanceof Object) {
      container[key] = val;
    }
  }
docs: Add `val` to `container`.
  
  If `container` is an array, `val` will be appended.  Otherwise, if
  `container` is an object, `val` will be set as the value of `key`.
  
  @param {Object|Array} container
  @param {String} key
  @param {Mixed} val
  @api private