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| 1 | +import { createElement, setFeatureFlagForTest } from 'lwc'; |
| 2 | +import Reactive from 'x/reactive'; |
| 3 | +import NonReactive from 'x/nonReactive'; |
| 4 | +import Container from 'x/container'; |
| 5 | +import Parent from 'x/parent'; |
| 6 | +import Child from 'x/child'; |
| 7 | +import DuplicateSignalOnTemplate from 'x/duplicateSignalOnTemplate'; |
| 8 | +import List from 'x/list'; |
| 9 | + |
| 10 | +// Note for testing purposes the signal implementation uses LWC module resolution to simplify things. |
| 11 | +// In production the signal will come from a 3rd party library. |
| 12 | +import { Signal } from 'x/signal'; |
| 13 | + |
| 14 | +if (process.env.ENABLE_EXPERIMENTAL_SIGNALS) { |
| 15 | + describe('signal protocol', () => { |
| 16 | + beforeAll(() => { |
| 17 | + setFeatureFlagForTest('ENABLE_EXPERIMENTAL_SIGNALS', true); |
| 18 | + }); |
| 19 | + |
| 20 | + afterAll(() => { |
| 21 | + setFeatureFlagForTest('ENABLE_EXPERIMENTAL_SIGNALS', false); |
| 22 | + }); |
| 23 | + |
| 24 | + describe('lwc engine subscribes template re-render callback when signal is bound to an LWC and used on a template', () => { |
| 25 | + [ |
| 26 | + { |
| 27 | + testName: |
| 28 | + 'contains a getter that references a bound signal (.value on template)', |
| 29 | + flag: 'showGetterSignal', |
| 30 | + }, |
| 31 | + { |
| 32 | + testName: 'contains a getter that references a bound signal value', |
| 33 | + flag: 'showOnlyUsingSignalNotValue', |
| 34 | + }, |
| 35 | + { |
| 36 | + testName: 'contains a signal with @api annotation (.value on template)', |
| 37 | + flag: 'showApiSignal', |
| 38 | + }, |
| 39 | + { |
| 40 | + testName: 'contains a signal with @track annotation (.value on template)', |
| 41 | + flag: 'showTrackedSignal', |
| 42 | + }, |
| 43 | + { |
| 44 | + testName: |
| 45 | + 'contains an observed field referencing a signal (.value on template)', |
| 46 | + flag: 'showObservedFieldSignal', |
| 47 | + }, |
| 48 | + { |
| 49 | + testName: |
| 50 | + 'contains a direct reference to a signal (not .value) in the template', |
| 51 | + flag: 'showOnlyUsingSignalNotValue', |
| 52 | + }, |
| 53 | + ].forEach(({ testName, flag }) => { |
| 54 | + // Test all ways of binding signal to an LWC + template that cause re-rendering |
| 55 | + it(testName, async () => { |
| 56 | + const elm = createElement('x-reactive', { is: Reactive }); |
| 57 | + document.body.appendChild(elm); |
| 58 | + await Promise.resolve(); |
| 59 | + |
| 60 | + expect(elm.getSignalSubscriberCount()).toBe(0); |
| 61 | + elm[flag] = true; |
| 62 | + await Promise.resolve(); |
| 63 | + |
| 64 | + // the engine will automatically subscribe the re-render callback |
| 65 | + expect(elm.getSignalSubscriberCount()).toBe(1); |
| 66 | + }); |
| 67 | + }); |
| 68 | + }); |
| 69 | + |
| 70 | + it('lwc engine should automatically unsubscribe the re-render callback if signal is not used on a template', async () => { |
| 71 | + const elm = createElement('x-reactive', { is: Reactive }); |
| 72 | + elm.showObservedFieldSignal = true; |
| 73 | + document.body.appendChild(elm); |
| 74 | + await Promise.resolve(); |
| 75 | + |
| 76 | + expect(elm.getSignalSubscriberCount()).toBe(1); |
| 77 | + elm.showObservedFieldSignal = false; |
| 78 | + await Promise.resolve(); |
| 79 | + |
| 80 | + expect(elm.getSignalSubscriberCount()).toBe(0); |
| 81 | + document.body.removeChild(elm); |
| 82 | + }); |
| 83 | + |
| 84 | + it('lwc engine does not subscribe re-render callback if signal is not used on a template', async () => { |
| 85 | + const elm = createElement('x-non-reactive', { is: NonReactive }); |
| 86 | + document.body.appendChild(elm); |
| 87 | + await Promise.resolve(); |
| 88 | + |
| 89 | + expect(elm.getSignalSubscriberCount()).toBe(0); |
| 90 | + }); |
| 91 | + |
| 92 | + it('only the components referencing a signal should re-render', async () => { |
| 93 | + const container = createElement('x-container', { is: Container }); |
| 94 | + const signalElm = createElement('x-signal-elm', { is: Child }); |
| 95 | + const signal = new Signal('initial value'); |
| 96 | + signalElm.signal = signal; |
| 97 | + container.appendChild(signalElm); |
| 98 | + document.body.appendChild(container); |
| 99 | + |
| 100 | + await Promise.resolve(); |
| 101 | + |
| 102 | + expect(container.renderCount).toBe(1); |
| 103 | + expect(signalElm.renderCount).toBe(1); |
| 104 | + expect(signal.getSubscriberCount()).toBe(1); |
| 105 | + |
| 106 | + signal.value = 'updated value'; |
| 107 | + await Promise.resolve(); |
| 108 | + |
| 109 | + expect(container.renderCount).toBe(1); |
| 110 | + expect(signalElm.renderCount).toBe(2); |
| 111 | + expect(signal.getSubscriberCount()).toBe(1); |
| 112 | + }); |
| 113 | + |
| 114 | + it('only subscribes the re-render callback a single time when signal is referenced multiple times on a template', async () => { |
| 115 | + const elm = createElement('x-duplicate-signals-on-template', { |
| 116 | + is: DuplicateSignalOnTemplate, |
| 117 | + }); |
| 118 | + document.body.appendChild(elm); |
| 119 | + await Promise.resolve(); |
| 120 | + |
| 121 | + expect(elm.renderCount).toBe(1); |
| 122 | + expect(elm.getSignalSubscriberCount()).toBe(1); |
| 123 | + expect(elm.getSignalRemovedSubscriberCount()).toBe(0); |
| 124 | + |
| 125 | + elm.updateSignalValue(); |
| 126 | + await Promise.resolve(); |
| 127 | + |
| 128 | + expect(elm.renderCount).toBe(2); |
| 129 | + expect(elm.getSignalSubscriberCount()).toBe(1); |
| 130 | + expect(elm.getSignalRemovedSubscriberCount()).toBe(1); |
| 131 | + }); |
| 132 | + |
| 133 | + it('only subscribes re-render callback a single time when signal is referenced multiple times in a list', async () => { |
| 134 | + const elm = createElement('x-list', { is: List }); |
| 135 | + const signal = new Signal('initial value'); |
| 136 | + elm.signal = signal; |
| 137 | + document.body.appendChild(elm); |
| 138 | + await Promise.resolve(); |
| 139 | + |
| 140 | + expect(signal.getSubscriberCount()).toBe(1); |
| 141 | + expect(signal.getRemovedSubscriberCount()).toBe(0); |
| 142 | + |
| 143 | + document.body.removeChild(elm); |
| 144 | + await Promise.resolve(); |
| 145 | + |
| 146 | + expect(signal.getSubscriberCount()).toBe(0); |
| 147 | + expect(signal.getRemovedSubscriberCount()).toBe(1); |
| 148 | + }); |
| 149 | + |
| 150 | + it('unsubscribes when element is removed from the dom', async () => { |
| 151 | + const elm = createElement('x-child', { is: Child }); |
| 152 | + const signal = new Signal('initial value'); |
| 153 | + elm.signal = signal; |
| 154 | + document.body.appendChild(elm); |
| 155 | + await Promise.resolve(); |
| 156 | + |
| 157 | + expect(signal.getSubscriberCount()).toBe(1); |
| 158 | + expect(signal.getRemovedSubscriberCount()).toBe(0); |
| 159 | + |
| 160 | + document.body.removeChild(elm); |
| 161 | + await Promise.resolve(); |
| 162 | + |
| 163 | + expect(signal.getSubscriberCount()).toBe(0); |
| 164 | + expect(signal.getRemovedSubscriberCount()).toBe(1); |
| 165 | + }); |
| 166 | + |
| 167 | + it('on template re-render unsubscribes all components where signal is not present on the template', async () => { |
| 168 | + const elm = createElement('x-parent', { is: Parent }); |
| 169 | + elm.showChild = true; |
| 170 | + |
| 171 | + document.body.appendChild(elm); |
| 172 | + await Promise.resolve(); |
| 173 | + |
| 174 | + // subscribed both parent and child |
| 175 | + // as long as parent contains reference to the signal, even if it's just to pass it to a child |
| 176 | + // it will be subscribed. |
| 177 | + expect(elm.getSignalSubscriberCount()).toBe(2); |
| 178 | + expect(elm.getSignalRemovedSubscriberCount()).toBe(0); |
| 179 | + |
| 180 | + elm.showChild = false; |
| 181 | + await Promise.resolve(); |
| 182 | + |
| 183 | + // The signal is not being used on the parent template anymore so it will be removed |
| 184 | + expect(elm.getSignalSubscriberCount()).toBe(0); |
| 185 | + expect(elm.getSignalRemovedSubscriberCount()).toBe(2); |
| 186 | + }); |
| 187 | + |
| 188 | + it('does not subscribe if the signal shape is incorrect', async () => { |
| 189 | + const elm = createElement('x-child', { is: Child }); |
| 190 | + const subscribe = jasmine.createSpy(); |
| 191 | + // Note the signals property is value's' and not value |
| 192 | + const signal = { values: 'initial value', subscribe }; |
| 193 | + elm.signal = signal; |
| 194 | + document.body.appendChild(elm); |
| 195 | + await Promise.resolve(); |
| 196 | + |
| 197 | + expect(subscribe).not.toHaveBeenCalled(); |
| 198 | + }); |
| 199 | + }); |
| 200 | +} else { |
| 201 | + describe('ENABLE_EXPERIMENTAL_SIGNALS not set', () => { |
| 202 | + beforeAll(() => { |
| 203 | + setFeatureFlagForTest('ENABLE_EXPERIMENTAL_SIGNALS', false); |
| 204 | + }); |
| 205 | + |
| 206 | + it('does not subscribe or unsubscribe if feature flag is disabled', async () => { |
| 207 | + const elm = createElement('x-child', { is: Child }); |
| 208 | + const signal = new Signal('initial value'); |
| 209 | + elm.signal = signal; |
| 210 | + document.body.appendChild(elm); |
| 211 | + await Promise.resolve(); |
| 212 | + |
| 213 | + expect(signal.getSubscriberCount()).toBe(0); |
| 214 | + expect(signal.getRemovedSubscriberCount()).toBe(0); |
| 215 | + |
| 216 | + document.body.removeChild(elm); |
| 217 | + await Promise.resolve(); |
| 218 | + |
| 219 | + expect(signal.getSubscriberCount()).toBe(0); |
| 220 | + expect(signal.getRemovedSubscriberCount()).toBe(0); |
| 221 | + }); |
| 222 | + }); |
| 223 | +} |
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