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| 1 | +import { beforeAll, describe, expect, it, vi } from 'vitest'; |
| 2 | +import { debounce } from '../../../src/utils/debounce'; |
| 3 | + |
| 4 | +describe('Unit | util | debounce', () => { |
| 5 | + beforeAll(() => { |
| 6 | + vi.useFakeTimers(); |
| 7 | + }); |
| 8 | + |
| 9 | + it('delay the execution of the passed callback function by the passed minDelay', () => { |
| 10 | + const callback = vi.fn(); |
| 11 | + const debouncedCallback = debounce(callback, 100); |
| 12 | + debouncedCallback(); |
| 13 | + expect(callback).not.toHaveBeenCalled(); |
| 14 | + |
| 15 | + vi.advanceTimersByTime(99); |
| 16 | + expect(callback).not.toHaveBeenCalled(); |
| 17 | + |
| 18 | + vi.advanceTimersByTime(1); |
| 19 | + expect(callback).toHaveBeenCalled(); |
| 20 | + }); |
| 21 | + |
| 22 | + it('should invoke the callback at latest by maxWait, if the option is specified', () => { |
| 23 | + const callback = vi.fn(); |
| 24 | + const debouncedCallback = debounce(callback, 100, { maxWait: 150 }); |
| 25 | + debouncedCallback(); |
| 26 | + expect(callback).not.toHaveBeenCalled(); |
| 27 | + |
| 28 | + vi.advanceTimersByTime(98); |
| 29 | + expect(callback).not.toHaveBeenCalled(); |
| 30 | + |
| 31 | + debouncedCallback(); |
| 32 | + |
| 33 | + vi.advanceTimersByTime(1); |
| 34 | + expect(callback).not.toHaveBeenCalled(); |
| 35 | + |
| 36 | + vi.advanceTimersByTime(49); |
| 37 | + // at this time, the callback shouldn't be invoked and with a new call, it should be debounced further. |
| 38 | + debouncedCallback(); |
| 39 | + expect(callback).not.toHaveBeenCalled(); |
| 40 | + |
| 41 | + // But because the maxWait is reached, the callback should nevertheless be invoked. |
| 42 | + vi.advanceTimersByTime(10); |
| 43 | + expect(callback).toHaveBeenCalled(); |
| 44 | + }); |
| 45 | + |
| 46 | + it('should not invoke the callback as long as it is debounced and no maxWait option is specified', () => { |
| 47 | + const callback = vi.fn(); |
| 48 | + const debouncedCallback = debounce(callback, 100); |
| 49 | + debouncedCallback(); |
| 50 | + expect(callback).not.toHaveBeenCalled(); |
| 51 | + |
| 52 | + vi.advanceTimersByTime(99); |
| 53 | + expect(callback).not.toHaveBeenCalled(); |
| 54 | + |
| 55 | + debouncedCallback(); |
| 56 | + |
| 57 | + vi.advanceTimersByTime(1); |
| 58 | + expect(callback).not.toHaveBeenCalled(); |
| 59 | + |
| 60 | + vi.advanceTimersByTime(98); |
| 61 | + debouncedCallback(); |
| 62 | + expect(callback).not.toHaveBeenCalled(); |
| 63 | + |
| 64 | + vi.advanceTimersByTime(99); |
| 65 | + expect(callback).not.toHaveBeenCalled(); |
| 66 | + debouncedCallback(); |
| 67 | + |
| 68 | + vi.advanceTimersByTime(100); |
| 69 | + expect(callback).toHaveBeenCalled(); |
| 70 | + }); |
| 71 | + |
| 72 | + it('should invoke the callback as soon as callback.flush() is called', () => { |
| 73 | + const callback = vi.fn(); |
| 74 | + const debouncedCallback = debounce(callback, 100, { maxWait: 200 }); |
| 75 | + debouncedCallback(); |
| 76 | + expect(callback).not.toHaveBeenCalled(); |
| 77 | + |
| 78 | + vi.advanceTimersByTime(10); |
| 79 | + expect(callback).not.toHaveBeenCalled(); |
| 80 | + |
| 81 | + debouncedCallback.flush(); |
| 82 | + expect(callback).toHaveBeenCalled(); |
| 83 | + }); |
| 84 | + |
| 85 | + it('should not invoke the callback, if callback.cancel() is called', () => { |
| 86 | + const callback = vi.fn(); |
| 87 | + const debouncedCallback = debounce(callback, 100, { maxWait: 200 }); |
| 88 | + debouncedCallback(); |
| 89 | + expect(callback).not.toHaveBeenCalled(); |
| 90 | + |
| 91 | + vi.advanceTimersByTime(99); |
| 92 | + expect(callback).not.toHaveBeenCalled(); |
| 93 | + |
| 94 | + // If the callback is canceled, it should not be invoked after the minwait |
| 95 | + debouncedCallback.cancel(); |
| 96 | + vi.advanceTimersByTime(1); |
| 97 | + expect(callback).not.toHaveBeenCalled(); |
| 98 | + |
| 99 | + // And it should also not be invoked after the maxWait |
| 100 | + vi.advanceTimersByTime(500); |
| 101 | + expect(callback).not.toHaveBeenCalled(); |
| 102 | + }); |
| 103 | + |
| 104 | + it("should return the callback's return value when calling callback.flush()", () => { |
| 105 | + const callback = vi.fn().mockReturnValue('foo'); |
| 106 | + const debouncedCallback = debounce(callback, 100); |
| 107 | + |
| 108 | + debouncedCallback(); |
| 109 | + |
| 110 | + const returnValue = debouncedCallback.flush(); |
| 111 | + expect(returnValue).toBe('foo'); |
| 112 | + }); |
| 113 | + |
| 114 | + it('should return the callbacks return value on subsequent calls of the debounced function', () => { |
| 115 | + const callback = vi.fn().mockReturnValue('foo'); |
| 116 | + const debouncedCallback = debounce(callback, 100); |
| 117 | + |
| 118 | + const returnValue1 = debouncedCallback(); |
| 119 | + expect(returnValue1).toBe(undefined); |
| 120 | + expect(callback).not.toHaveBeenCalled(); |
| 121 | + |
| 122 | + // now we expect the callback to have been invoked |
| 123 | + vi.advanceTimersByTime(200); |
| 124 | + expect(callback).toHaveBeenCalledTimes(1); |
| 125 | + |
| 126 | + // calling the debounced function now should return the return value of the callback execution |
| 127 | + const returnValue2 = debouncedCallback(); |
| 128 | + expect(returnValue2).toBe('foo'); |
| 129 | + expect(callback).toHaveBeenCalledTimes(1); |
| 130 | + |
| 131 | + // and the callback should also be invoked again |
| 132 | + vi.advanceTimersByTime(200); |
| 133 | + expect(callback).toHaveBeenCalledTimes(2); |
| 134 | + }); |
| 135 | + |
| 136 | + it('should handle return values of consecutive invocations without maxWait', () => { |
| 137 | + let i = 0; |
| 138 | + const callback = vi.fn().mockImplementation(() => { |
| 139 | + return `foo-${++i}`; |
| 140 | + }); |
| 141 | + const debouncedCallback = debounce(callback, 100); |
| 142 | + |
| 143 | + const returnValue0 = debouncedCallback(); |
| 144 | + expect(returnValue0).toBe(undefined); |
| 145 | + expect(callback).not.toHaveBeenCalled(); |
| 146 | + |
| 147 | + // now we expect the callback to have been invoked |
| 148 | + vi.advanceTimersByTime(200); |
| 149 | + expect(callback).toHaveBeenCalledTimes(1); |
| 150 | + |
| 151 | + // calling the debounced function now should return the return value of the callback execution |
| 152 | + const returnValue1 = debouncedCallback(); |
| 153 | + expect(returnValue1).toBe('foo-1'); |
| 154 | + expect(callback).toHaveBeenCalledTimes(1); |
| 155 | + |
| 156 | + vi.advanceTimersByTime(1); |
| 157 | + const returnValue2 = debouncedCallback(); |
| 158 | + expect(returnValue2).toBe('foo-1'); |
| 159 | + expect(callback).toHaveBeenCalledTimes(1); |
| 160 | + |
| 161 | + // and the callback should also be invoked again |
| 162 | + vi.advanceTimersByTime(200); |
| 163 | + const returnValue3 = debouncedCallback(); |
| 164 | + expect(returnValue3).toBe('foo-2'); |
| 165 | + expect(callback).toHaveBeenCalledTimes(2); |
| 166 | + }); |
| 167 | + |
| 168 | + it('should handle return values of consecutive invocations with maxWait', () => { |
| 169 | + let i = 0; |
| 170 | + const callback = vi.fn().mockImplementation(() => { |
| 171 | + return `foo-${++i}`; |
| 172 | + }); |
| 173 | + const debouncedCallback = debounce(callback, 150, { maxWait: 200 }); |
| 174 | + |
| 175 | + const returnValue0 = debouncedCallback(); |
| 176 | + expect(returnValue0).toBe(undefined); |
| 177 | + expect(callback).not.toHaveBeenCalled(); |
| 178 | + |
| 179 | + // now we expect the callback to have been invoked |
| 180 | + vi.advanceTimersByTime(149); |
| 181 | + const returnValue1 = debouncedCallback(); |
| 182 | + expect(returnValue1).toBe(undefined); |
| 183 | + expect(callback).not.toHaveBeenCalled(); |
| 184 | + |
| 185 | + // calling the debounced function now should return the return value of the callback execution |
| 186 | + // as it was executed because of maxWait |
| 187 | + vi.advanceTimersByTime(51); |
| 188 | + const returnValue2 = debouncedCallback(); |
| 189 | + expect(returnValue2).toBe('foo-1'); |
| 190 | + expect(callback).toHaveBeenCalledTimes(1); |
| 191 | + |
| 192 | + // at this point (100ms after the last debounce call), nothing should have happened |
| 193 | + vi.advanceTimersByTime(100); |
| 194 | + const returnValue3 = debouncedCallback(); |
| 195 | + expect(returnValue3).toBe('foo-1'); |
| 196 | + expect(callback).toHaveBeenCalledTimes(1); |
| 197 | + |
| 198 | + // and the callback should now have been invoked again |
| 199 | + vi.advanceTimersByTime(150); |
| 200 | + const returnValue4 = debouncedCallback(); |
| 201 | + expect(returnValue4).toBe('foo-2'); |
| 202 | + expect(callback).toHaveBeenCalledTimes(2); |
| 203 | + }); |
| 204 | + |
| 205 | + it('should handle return values of consecutive invocations after a cancellation', () => { |
| 206 | + let i = 0; |
| 207 | + const callback = vi.fn().mockImplementation(() => { |
| 208 | + return `foo-${++i}`; |
| 209 | + }); |
| 210 | + const debouncedCallback = debounce(callback, 150, { maxWait: 200 }); |
| 211 | + |
| 212 | + const returnValue0 = debouncedCallback(); |
| 213 | + expect(returnValue0).toBe(undefined); |
| 214 | + expect(callback).not.toHaveBeenCalled(); |
| 215 | + |
| 216 | + // now we expect the callback to have been invoked |
| 217 | + vi.advanceTimersByTime(149); |
| 218 | + const returnValue1 = debouncedCallback(); |
| 219 | + expect(returnValue1).toBe(undefined); |
| 220 | + expect(callback).not.toHaveBeenCalled(); |
| 221 | + |
| 222 | + debouncedCallback.cancel(); |
| 223 | + |
| 224 | + // calling the debounced function now still return undefined because we cancelled the invocation |
| 225 | + vi.advanceTimersByTime(51); |
| 226 | + const returnValue2 = debouncedCallback(); |
| 227 | + expect(returnValue2).toBe(undefined); |
| 228 | + expect(callback).not.toHaveBeenCalled(); |
| 229 | + |
| 230 | + // and the callback should also be invoked again |
| 231 | + vi.advanceTimersByTime(150); |
| 232 | + const returnValue3 = debouncedCallback(); |
| 233 | + expect(returnValue3).toBe('foo-1'); |
| 234 | + expect(callback).toHaveBeenCalledTimes(1); |
| 235 | + }); |
| 236 | + |
| 237 | + it('should handle the return value of calling flush after cancelling', () => { |
| 238 | + const callback = vi.fn().mockReturnValue('foo'); |
| 239 | + const debouncedCallback = debounce(callback, 100); |
| 240 | + |
| 241 | + debouncedCallback(); |
| 242 | + debouncedCallback.cancel(); |
| 243 | + |
| 244 | + const returnValue = debouncedCallback.flush(); |
| 245 | + expect(returnValue).toBe(undefined); |
| 246 | + }); |
| 247 | + |
| 248 | + it('should handle equal wait and maxWait values and only invoke func once', () => { |
| 249 | + const callback = vi.fn().mockReturnValue('foo'); |
| 250 | + const debouncedCallback = debounce(callback, 100, { maxWait: 100 }); |
| 251 | + |
| 252 | + debouncedCallback(); |
| 253 | + vi.advanceTimersByTime(25); |
| 254 | + debouncedCallback(); |
| 255 | + vi.advanceTimersByTime(25); |
| 256 | + debouncedCallback(); |
| 257 | + vi.advanceTimersByTime(25); |
| 258 | + debouncedCallback(); |
| 259 | + vi.advanceTimersByTime(25); |
| 260 | + |
| 261 | + expect(callback).toHaveBeenCalledTimes(1); |
| 262 | + |
| 263 | + const retval = debouncedCallback(); |
| 264 | + expect(retval).toBe('foo'); |
| 265 | + |
| 266 | + vi.advanceTimersByTime(25); |
| 267 | + debouncedCallback(); |
| 268 | + vi.advanceTimersByTime(25); |
| 269 | + debouncedCallback(); |
| 270 | + vi.advanceTimersByTime(25); |
| 271 | + debouncedCallback(); |
| 272 | + vi.advanceTimersByTime(25); |
| 273 | + |
| 274 | + expect(callback).toHaveBeenCalledTimes(2); |
| 275 | + }); |
| 276 | +}); |
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