Added the life-cycle interface of an extension

app/assets/javascripts/editor/source_editor_extension.js

@@ -14,4 +14,52 @@ export default class EditorExtension {
   getApi() {
     return this.obj.provides();
   }
+
+  /**
+   * THE LIFE-CYCLE CALLBACKS
+   */
+
+  /**
+   * Is called before the extension gets used by an instance,
+   * Use `onSetup` to setup Monaco directly:
+   * actions, keystrokes, update options, etc.
+   * Is called only once before the extension gets registered
+   *
+   * @param { Object } [options]  The setupOptions object
+   * @param { Object } [instance] The Source Editor instance
+   */
+  // eslint-disable-next-line class-methods-use-this,no-unused-vars
+  onSetup(options, instance) {}
+
+  /**
+   * The first thing called after the extension is
+   * registered and used by an instance.
+   * Is called every time the extension is applied
+   *
+   * @param { Object } [instance] The Source Editor instance
+   */
+  // eslint-disable-next-line class-methods-use-this,no-unused-vars
+  onUse(instance) {}
+
+  /**
+   * Is called before un-using an extension. Can be used for time-critical
+   * actions like cleanup, reverting visual changes, and other user-facing
+   * updates.
+   *
+   * @param { Object } [instance] The Source Editor instance
+   */
+  // eslint-disable-next-line class-methods-use-this,no-unused-vars
+  onBeforeUnuse(instance) {}
+
+  /**
+   * Is called right after an extension is removed from an instance (un-used)
+   * Can be used for non time-critical tasks like cleanup on the Monaco level
+   * (removing actions, keystrokes, etc.).
+   * onUnuse() will be executed during the browser's idle period
+   * (https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback)
+   *
+   * @param { Object } [instance] The Source Editor instance
+   */
+  // eslint-disable-next-line class-methods-use-this,no-unused-vars
+  onUnuse(instance) {}
 }