Bug 1874276 - Convert PlacesFeed into an ESM. r=thecount,places-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D199360

.eslintrc.js

@@ -739,7 +739,7 @@ module.exports = {
         "browser/components/newtab/content-src/components/DiscoveryStreamComponents/TopSites/TopSites.jsx ",
         "browser/components/newtab/content-src/components/TopSites/TopSiteForm.jsx ",
         "browser/components/newtab/lib/CFRMessageProvider.sys.mjs ",
-        "browser/components/newtab/lib/PlacesFeed.jsm ",
+        "browser/components/newtab/lib/PlacesFeed.sys.mjs ",
         "browser/components/originattributes/test/browser/browser_broadcastChannel.js",
         "browser/components/originattributes/test/browser/browser_cache.js",
         "browser/components/originattributes/test/browser/browser_favicon_firstParty.js",

browser/components/newtab/karma.mc.config.js

@@ -134,9 +134,9 @@ module.exports = function (config) {
               branches: 78,
             },
             /**
-             * PlacesFeed.jsm is tested via an xpcshell test
+             * PlacesFeed.sys.mjs is tested via an xpcshell test
              */
-            "lib/PlacesFeed.jsm": {
+            "lib/PlacesFeed.sys.mjs": {
               statements: 7,
               lines: 7,
               functions: 8,

browser/components/newtab/lib/ActivityStream.jsm

@@ -14,6 +14,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
   DefaultPrefs: "resource://activity-stream/lib/ActivityStreamPrefs.sys.mjs",
   HighlightsFeed: "resource://activity-stream/lib/HighlightsFeed.sys.mjs",
   NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
+  PlacesFeed: "resource://activity-stream/lib/PlacesFeed.sys.mjs",
   Region: "resource://gre/modules/Region.sys.mjs",
   TelemetryFeed: "resource://activity-stream/lib/TelemetryFeed.sys.mjs",
 });
@@ -43,11 +44,6 @@ ChromeUtils.defineModuleGetter(
   "RecommendationProvider",
   "resource://activity-stream/lib/RecommendationProvider.jsm"
 );
-ChromeUtils.defineModuleGetter(
-  lazy,
-  "PlacesFeed",
-  "resource://activity-stream/lib/PlacesFeed.jsm"
-);
 ChromeUtils.defineModuleGetter(
   lazy,
   "PrefsFeed",

browser/components/newtab/lib/PlacesFeed.sys.mjs

@@ -1,18 +1,24 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-"use strict";
 
-const {
-  actionCreators: ac,
-  actionTypes: at,
-  actionUtils: au,
-} = ChromeUtils.importESModule(
-  "resource://activity-stream/common/Actions.sys.mjs"
-);
+import {
+  actionCreators as ac,
+  actionTypes as at,
+  actionUtils as au,
+} from "resource://activity-stream/common/Actions.sys.mjs";
+
 const { shortURL } = ChromeUtils.import(
   "resource://activity-stream/lib/ShortURL.jsm"
 );
+
+// We use importESModule here instead of static import so that
+// the Karma test environment won't choke on this module. This
+// is because the Karma test environment already stubs out
+// AboutNewTab, and overrides importESModule to be a no-op (which
+// can't be done for a static import statement).
+
+// eslint-disable-next-line mozilla/use-static-import
 const { AboutNewTab } = ChromeUtils.importESModule(
   "resource:///modules/AboutNewTab.sys.mjs"
 );
@@ -133,7 +139,7 @@ class PlacesObserver {
   }
 }
 
-class PlacesFeed {
+export class PlacesFeed {
   constructor() {
     this.placesChangedTimer = null;
     this.customDispatch = this.customDispatch.bind(this);
@@ -562,5 +568,3 @@ class PlacesFeed {
 
 // Exported for testing only
 PlacesFeed.PlacesObserver = PlacesObserver;
-
-const EXPORTED_SYMBOLS = ["PlacesFeed"];

browser/components/newtab/test/unit/lib/ActivityStream.test.js

@@ -8,7 +8,7 @@ import { DefaultPrefs } from "lib/ActivityStreamPrefs.sys.mjs";
 import { NewTabInit } from "lib/NewTabInit.jsm";
 import { SectionsFeed } from "lib/SectionsManager.jsm";
 import { RecommendationProvider } from "lib/RecommendationProvider.jsm";
-import { PlacesFeed } from "lib/PlacesFeed.jsm";
+import { PlacesFeed } from "lib/PlacesFeed.sys.mjs";
 import { PrefsFeed } from "lib/PrefsFeed.jsm";
 import { SystemTickFeed } from "lib/SystemTickFeed.jsm";
 import { TelemetryFeed } from "lib/TelemetryFeed.sys.mjs";

browser/components/newtab/test/xpcshell/test_PlacesFeed.js

@@ -14,6 +14,7 @@ ChromeUtils.defineESModuleGetters(this, {
   NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
   PartnerLinkAttribution: "resource:///modules/PartnerLinkAttribution.sys.mjs",
   pktApi: "chrome://pocket/content/pktApi.sys.mjs",
+  PlacesFeed: "resource://activity-stream/lib/PlacesFeed.sys.mjs",
   PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
   PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.sys.mjs",
   SearchService: "resource://gre/modules/SearchService.sys.mjs",
@@ -21,10 +22,6 @@ ChromeUtils.defineESModuleGetters(this, {
   TestUtils: "resource://testing-common/TestUtils.sys.mjs",
 });
 
-const { PlacesFeed } = ChromeUtils.import(
-  "resource://activity-stream/lib/PlacesFeed.jsm"
-);
-
 const { PlacesObserver } = PlacesFeed;
 
 const FAKE_BOOKMARK = {