70 lines
1.5 KiB
TypeScript
70 lines
1.5 KiB
TypeScript
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
|
|
import { debounce } from './debounce';
|
|
|
|
describe('debounce', () => {
|
|
beforeEach(() => {
|
|
vi.useFakeTimers();
|
|
});
|
|
|
|
afterEach(() => {
|
|
vi.useRealTimers();
|
|
});
|
|
|
|
it('does not fire before the delay has elapsed', () => {
|
|
const fn = vi.fn();
|
|
const debounced = debounce(fn, 200);
|
|
|
|
debounced();
|
|
vi.advanceTimersByTime(199);
|
|
|
|
expect(fn).not.toHaveBeenCalled();
|
|
});
|
|
|
|
it('fires exactly once after the delay', () => {
|
|
const fn = vi.fn();
|
|
const debounced = debounce(fn, 200);
|
|
|
|
debounced();
|
|
vi.advanceTimersByTime(200);
|
|
|
|
expect(fn).toHaveBeenCalledTimes(1);
|
|
});
|
|
|
|
it('resets the timer on each call — fires only once after inactivity', () => {
|
|
const fn = vi.fn();
|
|
const debounced = debounce(fn, 200);
|
|
|
|
debounced();
|
|
vi.advanceTimersByTime(100);
|
|
debounced();
|
|
vi.advanceTimersByTime(100);
|
|
debounced();
|
|
vi.advanceTimersByTime(200);
|
|
|
|
expect(fn).toHaveBeenCalledTimes(1);
|
|
});
|
|
|
|
it('passes the latest arguments to the callback', () => {
|
|
const fn = vi.fn();
|
|
const debounced = debounce(fn, 200);
|
|
|
|
debounced('first');
|
|
debounced('second');
|
|
vi.advanceTimersByTime(200);
|
|
|
|
expect(fn).toHaveBeenCalledWith('second');
|
|
});
|
|
|
|
it('can fire again after the first invocation settles', () => {
|
|
const fn = vi.fn();
|
|
const debounced = debounce(fn, 200);
|
|
|
|
debounced();
|
|
vi.advanceTimersByTime(200);
|
|
debounced();
|
|
vi.advanceTimersByTime(200);
|
|
|
|
expect(fn).toHaveBeenCalledTimes(2);
|
|
});
|
|
});
|