Restored background.js boilerplate from template

.gitignore

@@ -1,4 +1,4 @@
 node_modules
 src/privileged/shieldUtils/jsm/StudyUtils.jsm
 src/privileged/shieldUtils/jsm/PioneerUtils.jsm
-src/background.js
+src/feature.js

src/background.js

@@ -0,0 +1,138 @@
+/* global getStudySetup, Feature */
+
+/**
+ *  Goal:  Implement an instrumented feature using `browser.study` API
+ *
+ *  Every runtime:
+ *  - Prepare
+ *
+ *    - listen for `onEndStudy` (study endings)
+ *    - listen for `study.onReady`
+ *
+ *  - Startup the feature
+ *
+ *    - attempt to `browser.study.setup` the study using our studySetup
+ *
+ *      - will fire EITHER
+ *        -  `endStudy` (`expired`, `ineligible`)
+ *        - onReady
+ *      - (see docs for `browser.study.setup`)
+ *
+ *    - onReady: configure the feature to match the `variation` study selected
+ *    - or, if we got an `onEndStudy` cleanup and uninstall.
+ *
+ *  During the feature:
+ *    - `sendTelemetry` to send pings
+ *    - `endStudy` to force an ending (for positive or negative reasons!)
+ *
+ *  Interesting things to try next:
+ *  - `browser.study.validateJSON` your pings before sending
+ *  - `endStudy` different endings in response to user action
+ *  - force an override of setup.testing to choose branches.
+ *
+ */
+
+class StudyLifeCycleHandler {
+  /**
+   * Listen to onEndStudy, onReady
+   * `browser.study.setup` fires onReady OR onEndStudy
+   *
+   * call `this.enableFeature` to actually do the feature/experience/ui.
+   */
+  constructor() {
+    /*
+     * IMPORTANT:  Listen for `onEndStudy` before calling `browser.study.setup`
+     * because:
+     * - `setup` can end with 'ineligible' due to 'allowEnroll' key in first session.
+     *
+     */
+    browser.study.onEndStudy.addListener(this.handleStudyEnding.bind(this));
+    browser.study.onReady.addListener(this.enableFeature.bind(this));
+  }
+
+  /**
+   * Cleanup
+   *
+   * (If you have privileged code, you might need to clean
+   *  that up as well.
+   * See:  https://firefox-source-docs.mozilla.org/toolkit/components/extensions/webextensions/lifecycle.html
+   *
+   * @returns {undefined}
+   */
+  async cleanup() {
+    await browser.storage.local.clear();
+    await feature.cleanup();
+  }
+
+  /**
+   *
+   * side effects
+   * - set up expiration alarms
+   * - make feature/experience/ui with the particular variation for this user.
+   *
+   * @param {object} studyInfo browser.study.studyInfo object
+   *
+   * @returns {undefined}
+   */
+  async enableFeature(studyInfo) {
+    console.log("enabling feature", studyInfo);
+    if (studyInfo.timeUntilExpire) {
+      const alarmName = `${browser.runtime.id}:studyExpiration`;
+      const alarmListener = async alarm => {
+        if (alarm.name === alarmName) {
+          console.log("study will expire now!");
+          browser.alarms.onAlarm.removeListener(alarmListener);
+          await browser.study.endStudy("expired");
+        }
+      };
+      browser.alarms.onAlarm.addListener(alarmListener);
+      browser.alarms.create(alarmName, {
+        delayInMinutes: studyInfo.timeUntilExpire / (1000 * 60),
+      });
+    }
+    feature.configure(studyInfo);
+  }
+
+  /** handles `study:end` signals
+   *
+   * - opens 'ending' urls (surveys, for example)
+   * - calls cleanup
+   *
+   * @param {object} ending An ending result
+   *
+   * @returns {undefined}
+   */
+  async handleStudyEnding(ending) {
+    console.log(`study wants to end:`, ending);
+    for (const url of ending.urls) {
+      await browser.tabs.create({ url });
+    }
+    switch (ending.endingName) {
+      // could have different actions depending on positive / ending names
+      default:
+        console.log(`the ending: ${ending.endingName}`);
+        await this.cleanup();
+        break;
+    }
+    // actually remove the addon.
+    console.log("about to actually uninstall");
+    return browser.management.uninstallSelf();
+  }
+}
+
+// construct. will be configured after setup.
+const feature = new Feature();
+
+/**
+ * Run every startup to get config and instantiate the feature
+ *
+ * @returns {undefined}
+ */
+async function onEveryExtensionLoad() {
+  new StudyLifeCycleHandler();
+
+  const studySetup = await getStudySetup();
+  console.log(`studySetup: ${JSON.stringify(studySetup)}`);
+  await browser.study.setup(studySetup);
+}
+onEveryExtensionLoad();