File size: 8,506 Bytes
1dbc34b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 | import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { debounce, throttle } from '../src/debounce.js';
describe('debounce', () => {
beforeEach(() => {
vi.useFakeTimers();
});
afterEach(() => {
vi.useRealTimers();
});
it('should delay function execution', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced();
expect(fn).not.toHaveBeenCalled();
vi.advanceTimersByTime(50);
expect(fn).not.toHaveBeenCalled();
vi.advanceTimersByTime(50);
expect(fn).toHaveBeenCalledTimes(1);
});
it('should reset timer on subsequent calls', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced();
vi.advanceTimersByTime(50);
debounced(); // Reset timer
vi.advanceTimersByTime(50);
expect(fn).not.toHaveBeenCalled();
vi.advanceTimersByTime(50);
expect(fn).toHaveBeenCalledTimes(1);
});
it('should pass arguments to the function', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced('arg1', 'arg2');
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledWith('arg1', 'arg2');
});
it('should use the latest arguments when called multiple times', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced('first');
debounced('second');
debounced('third');
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(1);
expect(fn).toHaveBeenCalledWith('third');
});
describe('leading option', () => {
it('should call function immediately when leading is true', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100, { leading: true });
debounced();
expect(fn).toHaveBeenCalledTimes(1);
});
it('should not call again until wait time has passed', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100, { leading: true, trailing: false });
debounced();
debounced();
debounced();
expect(fn).toHaveBeenCalledTimes(1);
vi.advanceTimersByTime(100);
debounced();
expect(fn).toHaveBeenCalledTimes(2);
});
it('should call both leading and trailing when both are true', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100, { leading: true, trailing: true });
debounced('leading');
expect(fn).toHaveBeenCalledTimes(1);
expect(fn).toHaveBeenLastCalledWith('leading');
debounced('trailing');
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(2);
expect(fn).toHaveBeenLastCalledWith('trailing');
});
});
describe('trailing option', () => {
it('should not call on trailing edge when trailing is false', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100, { trailing: false });
debounced();
vi.advanceTimersByTime(100);
expect(fn).not.toHaveBeenCalled();
});
});
describe('maxWait option', () => {
it('should invoke function after maxWait even with continuous calls', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100, { maxWait: 200 });
// Call continuously every 50ms
debounced();
vi.advanceTimersByTime(50);
debounced();
vi.advanceTimersByTime(50);
debounced();
vi.advanceTimersByTime(50);
debounced();
vi.advanceTimersByTime(50);
// After 200ms, maxWait should trigger
expect(fn).toHaveBeenCalledTimes(1);
});
it('should throw error if maxWait is less than wait', () => {
const fn = vi.fn();
expect(() => debounce(fn, 100, { maxWait: 50 })).toThrow(
'maxWait must be greater than or equal to wait'
);
});
});
describe('cancel method', () => {
it('should cancel pending invocation', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced();
debounced.cancel();
vi.advanceTimersByTime(100);
expect(fn).not.toHaveBeenCalled();
});
it('should reset state after cancel', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced('first');
debounced.cancel();
debounced('second');
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(1);
expect(fn).toHaveBeenCalledWith('second');
});
});
describe('flush method', () => {
it('should immediately invoke pending function', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced('value');
expect(fn).not.toHaveBeenCalled();
debounced.flush();
expect(fn).toHaveBeenCalledTimes(1);
expect(fn).toHaveBeenCalledWith('value');
});
it('should not invoke if no pending call', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced.flush();
expect(fn).not.toHaveBeenCalled();
});
it('should cancel timer after flush', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced();
debounced.flush();
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(1);
});
});
describe('pending method', () => {
it('should return true when there is a pending invocation', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
expect(debounced.pending()).toBe(false);
debounced();
expect(debounced.pending()).toBe(true);
});
it('should return false after invocation', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced();
vi.advanceTimersByTime(100);
expect(debounced.pending()).toBe(false);
});
it('should return false after cancel', () => {
const fn = vi.fn();
const debounced = debounce(fn, 100);
debounced();
debounced.cancel();
expect(debounced.pending()).toBe(false);
});
});
});
describe('throttle', () => {
beforeEach(() => {
vi.useFakeTimers();
});
afterEach(() => {
vi.useRealTimers();
});
it('should invoke function immediately by default', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100);
throttled();
expect(fn).toHaveBeenCalledTimes(1);
});
it('should not invoke again before wait time', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100);
throttled();
throttled();
throttled();
expect(fn).toHaveBeenCalledTimes(1);
});
it('should invoke on trailing edge with latest args', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100);
throttled('first');
expect(fn).toHaveBeenCalledWith('first');
throttled('second');
throttled('third');
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(2);
expect(fn).toHaveBeenLastCalledWith('third');
});
it('should respect leading option', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100, { leading: false });
throttled();
expect(fn).not.toHaveBeenCalled();
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(1);
});
it('should respect trailing option', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100, { trailing: false });
throttled('first');
throttled('second');
vi.advanceTimersByTime(100);
expect(fn).toHaveBeenCalledTimes(1);
expect(fn).toHaveBeenCalledWith('first');
});
it('should invoke at regular intervals during continuous calls', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100);
// Simulate continuous calls every 25ms for 250ms
for (let i = 0; i < 10; i++) {
throttled(i);
vi.advanceTimersByTime(25);
}
// Should be called at: 0ms (leading), 100ms, 200ms
// Plus one trailing call after the loop
expect(fn.mock.calls.length).toBeGreaterThanOrEqual(3);
});
it('should have cancel, flush, and pending methods', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100);
expect(typeof throttled.cancel).toBe('function');
expect(typeof throttled.flush).toBe('function');
expect(typeof throttled.pending).toBe('function');
});
it('should cancel pending invocation', () => {
const fn = vi.fn();
const throttled = throttle(fn, 100, { leading: false });
throttled();
throttled.cancel();
vi.advanceTimersByTime(100);
expect(fn).not.toHaveBeenCalled();
});
});
|