boomerangjs/doc/creating-plugins.md

boomerang always comes back, except when it hits something

Boomerang plugins can be used for adding core functionality (such
as ResourceTiming support) as well as for site-specific custom needs.

Use the below example for creating a new Boomerang plugin.

Once created, you can add the new plugin to your Boomerang build by adding
it to `plugins.json`.  See {@tutorial building} for more details.

```javascript
/**
 * Skeleton template for all boomerang plugins.
 *
 * Use this code as a starting point for your own plugins.
 */
(function() {
  // First, make sure BOOMR is actually defined.  It's possible that your plugin
  // is loaded before boomerang, in which case you'll need this.
  BOOMR = window.BOOMR || {};
  BOOMR.plugins = BOOMR.plugins || {};

  // A private object to encapsulate all your implementation details
  // This is optional, but the way we recommend you do it.
  var impl = {
  };

  //
  // Public exports
  //
  BOOMR.plugins.MyPlugin = {
    init: function(config) {
      // list of user configurable properties
      var properties = ["prop1", "prop2"];

      // This block is only needed if you actually have user configurable properties
      BOOMR.utils.pluginConfig(impl, config, "MyPlugin", properties);

      // Other initialization code here

      // Subscribe to any BOOMR events here.
      // Unless your code will explicitly be called by the developer
      // or by another plugin, you must to do this.

      return this;
    },

    // Any other public methods would be defined here

    is_complete: function() {
      // This method should determine if the plugin has completed doing what it
      // needs to do and return true if so or false otherwise
    }
  };
}());
```