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Extending the Widget

← Previous: Advanced Browser Side Topics

A "widget" is used to display selected snippets in the context of a page. The standard widget for snippets is automatically subclassed when you subclass snippets, and it works well: you can pick your own pieces by title or pull them in by tag. But what if we want to add a new field to the widget editor, or change its behavior more significantly?

Extending the Widget on the Browser Side

Here's how to do it on the browser side. Continuing with the "Stories" example above, we add this code to our constructor:

var superExtendWidget = self.extendWidget;

// extendWidget is called after the widget is constructed but
// before it is populated; you can override methods of the
// "widget" object here

self.extendWidget = function(widget) {
  // Call the original extendWidget method first. Maybe you're
  // subclassing something that has an interesting one.

  var superAfterCreatingEl = widget.afterCreatingEl;
  var superBeforeUpdate = widget.beforeUpdate;

  // afterCreatingEl is called after the widget's DOM element
  // comes into being. Let's add code to populate a checkbox
  // called "special"

  widget.afterCreatingEl = function() {

    widget.$newType = widget.$el.find('[name="special"]');



  // When the widget is previewed or saved we want to
  // make sure we record the state of the checkbox in
  // That's all we have to do to save it

  // Plumbing to use the same code for preview and save,
  // then call the right callback for each

  var superPrePreview = widget.prePreview;
  var superPreSave = widget.preSave;
  widget.prePreview = function(callback) {
    return beforeUpdate(superPrePreview, callback);
  widget.preSave = function(callback) {
    return beforeUpdate(superPreSave, callback);

  // Examine the checkbox and update the data object
  function beforeUpdate(callback, andThen) { = widget.$':checked');
    return callback(andThen);

Extending the Widget on the Server Side

You can also extend the behavior of widgets on the server side.

In your index.js file for the module in question, you can override the extendWidget method to manipulate the object that manages widgets of this type.

In this example we'll fetch only widgets that have a "special" boolean property if the "special" checkbox in the previous example is checked:

module.exports = stories;

function stories(options, callback) {
  return new stories.Stories(options, callback);

stories.Stories = function(options, callback) {
  var self = this;, options, null);

  self.extendWidget = function(widget) {
    // Make a note of the old addCriteria method
    var superAddCriteria = widget.addCriteria;
    widget.addCriteria = function(item, criteria, options) {
      // Call the old addCriteria method
      superAddCriteria(item, criteria, options);
      // Now add custom criteria
      if (item.special) {
        criteria.special = true;

  if (callback) {
    process.nextTick(function() { return callback(null); });

Other notable methods worth overriding and extending include renderWidget and load. See widget.js in the apostrophe-snippets module for details.

Next: Exporting Snippets →