[IMP] web: concurrency utils: add Deferred

Part-of: odoo/odoo#92475

addons/web/static/src/core/utils/concurrency.js

@@ -154,3 +154,18 @@ export class Race {
         return this.currentProm;
     }
 }
+
+/**
+ * Deferred is basically a resolvable/rejectable extension of Promise.
+ */
+export class Deferred {
+    constructor() {
+        let resolve;
+        let reject;
+        const prom = new Promise((res, rej) => {
+            resolve = res;
+            reject = rej;
+        });
+        return Object.assign(prom, { resolve, reject });
+    }
+}

addons/web/static/tests/core/utils/concurrency_tests.js

@@ -1,6 +1,6 @@
 /** @odoo-module **/
 
-import { Mutex, KeepLast, Race } from "@web/core/utils/concurrency";
+import { Deferred, Mutex, KeepLast, Race } from "@web/core/utils/concurrency";
 import { nextTick, makeDeferred } from "../../helpers/utils";
 
 QUnit.module("utils", () => {
@@ -312,4 +312,18 @@ QUnit.module("utils", () => {
         assert.verifySteps(["ok (44)"]);
         assert.strictEqual(race.getCurrentProm(), null);
     });
+
+    QUnit.test("Deferred: basic use", async function (assert) {
+        const def1 = new Deferred();
+        def1.then((v) => assert.step(`ok (${v})`));
+        def1.resolve(44);
+        await nextTick();
+        assert.verifySteps(["ok (44)"]);
+
+        const def2 = new Deferred();
+        def2.catch((v) => assert.step(`ko (${v})`));
+        def2.reject(44);
+        await nextTick();
+        assert.verifySteps(["ko (44)"]);
+    });
 });

addons/web/static/tests/helpers/utils.js

@@ -2,9 +2,10 @@
 
 import { browser } from "@web/core/browser/browser";
 import { isMacOS } from "@web/core/browser/feature_detection";
+import { download } from "@web/core/network/download";
+import { Deferred } from "@web/core/utils/concurrency";
 import { patch, unpatch } from "@web/core/utils/patch";
 import { registerCleanup } from "./cleanup";
-import { download } from "@web/core/network/download";
 
 const { App, onMounted, onPatched, useComponent } = owl;
 
@@ -150,15 +151,7 @@ export async function nextTick() {
 }
 
 export function makeDeferred() {
-    /** @type {(value:any)=>void} */
-    let resolve;
-    /** @type {(reason?:any)=>void} */
-    let reject;
-    const prom = new Promise((res, rej) => {
-        resolve = res;
-        reject = rej;
-    });
-    return Object.assign(prom, { resolve, reject });
+    return new Deferred();
 }
 
 function findElement(el, selector) {