Created an example extension for the end users

app/assets/javascripts/editor/extensions/example_source_editor_extension.js

+// THIS IS AN EXAMPLE
+//
+// This file contains a basic documented example of the Source Editor extensions'
+// API for your convenience. You can copy/paste it into your own file
+// and adjust as you see fit
+//
+
+export class MyFancyExtension {
+  /**
+   * 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 } [setupOptions]  The setupOptions object
+   * @param { Object } [instance] The Source Editor instance
+   */
+  // eslint-disable-next-line class-methods-use-this,no-unused-vars
+  onSetup(setupOptions, 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) {}
+
+  /**
+   * The public API of the extension: these are the methods that will be exposed
+   * to the end user
+   * @returns {Object}
+   */
+  provides() {
+    return {
+      basic: () => {
+        // The most basic method not depending on anything
+        // Use: instance.basic();
+        // eslint-disable-next-line @gitlab/require-i18n-strings
+        return 'Foo Bar';
+      },
+      basicWithProp: () => {
+        // The methods with access to the props of the extension.
+        // The props can be either hardcoded (for example in `onSetup`), or
+        // can be dynamically passed as part of `setupOptions` object when
+        // using the extension.
+        // Use: instance.use({ definition: MyFancyExtension, setupOptions: { foo: 'bar' }});
+        return this.foo;
+      },
+      basicWithPropsAsList: (prop1, prop2) => {
+        // Just a simple method with local props
+        // The props are passed as usually.
+        // Use: instance.basicWithPropsAsList(prop1, prop2);
+        // eslint-disable-next-line @gitlab/require-i18n-strings
+        return `The prop1 is ${prop1}; the prop2 is ${prop2}`;
+      },
+      basicWithInstance: (instance) => {
+        // The method accessing the instance methods: either own or provided
+        // by previously-registered extensions
+        // `instance` is always supplied to all methods in provides() as THE LAST
+        // argument.
+        // You don't need to explicitly pass instance to this method:
+        // Use: instance.basicWithInstance();
+        // eslint-disable-next-line @gitlab/require-i18n-strings
+        return `We have access to the whole Instance! ${instance.alpha()}`;
+      },
+      advancedWithInstanceAndProps: ({ author, book } = {}, firstname, lastname, instance) => {
+        // Advanced method where
+        // { author, book } — are the props passed as an object
+        // prop1, prop2    — are the props passed as simple list
+        // instance        — is automatically supplied, no need to pass it to
+        //                   the method explicitly
+        // Use: instance.advancedWithInstanceAndProps(
+        //     {
+        //       author: 'Franz Kafka',
+        //       book: 'The Transformation'
+        //     },
+        //     'Franz',
+        //     'Kafka'
+        //   );
+        return `
+The author is ${author}; the book is ${book}
+The author's name is ${firstname}; the last name is ${lastname}
+We have access to the whole Instance! For example, 'instance.alpha()': ${instance.alpha()}`;
+      },
+    };
+  }
+}

app/assets/javascripts/editor/source_editor_extension.js

@@ -14,52 +14,4 @@ export default class EditorExtension {
   get api() {
     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) {}
 }