Bug 1552424 - Go to file is slow when searching for a file. r=davidwalsh

Differential Revision: https://phabricator.services.mozilla.com/D32328

--HG--
extra : moz-landing-system : lando

devtools/client/debugger/src/components/QuickOpenModal.js

@@ -22,6 +22,7 @@ import {
   isSymbolsLoading,
   getContext,
 } from "../selectors";
+import { memoizeLast } from "../utils/memoizeLast";
 import { scrollList } from "../utils/result-list";
 import {
   formatSymbols,
@@ -131,11 +132,15 @@ export class QuickOpenModal extends Component<Props, State> {
     return query.split(":")[0];
   };
 
+  formatSources = memoizeLast((displayedSources, tabs) => {
+    const tabUrls = new Set(tabs.map((tab: Tab) => tab.url));
+    return formatSources(displayedSources, tabUrls);
+  });
+
   searchSources = (query: string) => {
     const { displayedSources, tabs } = this.props;
-    const tabUrls = new Set(tabs.map((tab: Tab) => tab.url));
-    const sources = formatSources(displayedSources, tabUrls);
 
+    const sources = this.formatSources(displayedSources, tabs);
     const results =
       query == "" ? sources : filter(sources, this.dropGoto(query));
     return this.setResults(results);

devtools/client/debugger/src/utils/memoizeLast.js

@@ -0,0 +1,27 @@
+/* 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/>. */
+
+export function memoizeLast(fn) {
+  let lastArgs: any[];
+  let lastResult: any;
+
+  const memoized = (...args) => {
+    if (
+      lastArgs &&
+      args.length === lastArgs.length &&
+      args.every((arg, i) => arg === lastArgs[i])
+    ) {
+      return lastResult;
+    }
+
+    lastArgs = args;
+    lastResult = fn(...args);
+
+    return lastResult;
+  };
+
+  return memoized;
+}
+
+export default memoizeLast;

devtools/client/debugger/src/utils/moz.build

@@ -33,6 +33,7 @@ CompiledModules(
     'log.js',
     'makeRecord.js',
     'memoize.js',
+    'memoizeLast.js',
     'memoizableAction.js',
     'path.js',
     'prefs.js',

devtools/client/debugger/src/utils/tests/memoizeLast.spec.js

@@ -0,0 +1,33 @@
+/* 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/>. */
+
+// @flow
+
+import { memoizeLast } from "../memoizeLast";
+
+const a = { number: 3 };
+const b = { number: 4 };
+
+function add(...numberObjects) {
+  return numberObjects.reduce((prev, cur) => prev + cur.number, 0);
+}
+
+describe("memozie", () => {
+  it("should re-calculate when a value changes", () => {
+    const mAdd = memoizeLast(add);
+    mAdd(a);
+    expect(mAdd(a)).toEqual(3);
+    mAdd(b);
+    expect(mAdd(b)).toEqual(4);
+  });
+
+  it("should only run once", () => {
+    const mockAdd = jest.fn(add);
+    const mAdd = memoizeLast(mockAdd);
+    mAdd(a);
+    mAdd(a);
+
+    expect(mockAdd.mock.calls[0]).toEqual([{ number: 3 }]);
+  });
+});