R Midhun Suresh
cd9a21ac93
So that we can create custom watchable objects that can add/remove event listeners as necessary.
100 lines
3.0 KiB
TypeScript
100 lines
3.0 KiB
TypeScript
/*
|
|
Copyright 2025 New Vector Ltd.
|
|
|
|
SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
|
|
Please see LICENSE files in the repository root for full details.
|
|
*/
|
|
|
|
import { expect, test, vi, vitest } from "vitest";
|
|
|
|
import { Watchable } from "./watchable";
|
|
|
|
test("initial value is set correctly", () => {
|
|
const watchable = new Watchable(42);
|
|
expect(watchable.value).toBe(42);
|
|
});
|
|
|
|
test("value can be updated", () => {
|
|
const watchable = new Watchable(100);
|
|
watchable.value = 200;
|
|
expect(watchable.value).toBe(200);
|
|
});
|
|
|
|
test("watchers are notified on value change", () => {
|
|
const watchable = new Watchable(1);
|
|
const listener = vitest.fn();
|
|
|
|
watchable.watch(listener);
|
|
watchable.value = 2; // This should trigger the listener
|
|
expect(listener).toHaveBeenCalledExactlyOnceWith(2);
|
|
|
|
watchable.unwatch(listener); // Clean up after the test
|
|
});
|
|
|
|
test("watchers are not notified if value does not change", () => {
|
|
const watchable = new Watchable(10);
|
|
const listener = vitest.fn();
|
|
|
|
watchable.watch(listener);
|
|
watchable.value = 10; // This should not trigger the listener
|
|
expect(listener).not.toHaveBeenCalled();
|
|
|
|
watchable.unwatch(listener); // Clean up after the test
|
|
});
|
|
|
|
test("when value is an object, shallow comparison works", () => {
|
|
const watchable = new Watchable({ a: 1, b: 2 });
|
|
const listener = vitest.fn();
|
|
watchable.watch(listener);
|
|
|
|
// Update with a new object that has the same properties
|
|
watchable.value = { a: 3, b: 2 }; // This should trigger the listener
|
|
expect(listener).toHaveBeenCalledExactlyOnceWith({ a: 3, b: 2 });
|
|
listener.mockClear();
|
|
watchable.value = { a: 3, b: 2 }; // This should not trigger the listener again
|
|
expect(listener).not.toHaveBeenCalled();
|
|
|
|
watchable.unwatch(listener); // Clean up after the test
|
|
});
|
|
|
|
test("onFirstWatch and onLastWatch are called when appropriate", () => {
|
|
const onFirstWatch = vi.fn();
|
|
const onLastWatch = vi.fn();
|
|
class CustomWatchable extends Watchable<number> {
|
|
protected onFirstWatch(): void {
|
|
onFirstWatch();
|
|
}
|
|
protected onLastWatch(): void {
|
|
onLastWatch();
|
|
}
|
|
}
|
|
|
|
const watchable = new CustomWatchable(10);
|
|
// No listeners yet, so expect no calls
|
|
expect(onFirstWatch).not.toHaveBeenCalled();
|
|
expect(onLastWatch).not.toHaveBeenCalled();
|
|
|
|
// Let's say that we have three listeners
|
|
const listeners = [vi.fn(), vi.fn(), vi.fn()];
|
|
|
|
// Let's add all of them via watch
|
|
for (const listener of listeners) {
|
|
watchable.watch(listener);
|
|
}
|
|
|
|
// Only expect onFirstWatch() to have been called once
|
|
expect(onFirstWatch).toHaveBeenCalledOnce();
|
|
|
|
// Let's remove all the listeners
|
|
for (const listener of listeners) {
|
|
watchable.unwatch(listener);
|
|
}
|
|
|
|
// Only expect onLastWatch to have been called once
|
|
expect(onLastWatch).toHaveBeenCalledOnce();
|
|
|
|
// Should call onFirstWatch again once we have more listeners
|
|
watchable.watch(vi.fn());
|
|
expect(onFirstWatch).toHaveBeenCalledTimes(2);
|
|
});
|