49 lines
1.7 KiB
TypeScript
49 lines
1.7 KiB
TypeScript
import { createSSRApp, defineComponent, h, computed, reactive } from 'vue'
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import { renderToString } from '../src/renderToString'
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// #5208 reported memory leak of keeping computed alive during SSR
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// so we made computed properties created during SSR non-reactive in
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// https://github.com/vuejs/core/commit/f4f0966b33863ac0fca6a20cf9e8ddfbb311ae87
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// However, the default caching leads to #5300 which is tested below.
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// In Vue 2, computed properties are simple getters during SSR - this can be
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// inefficient if an expensive computed is accessed multiple times during render,
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// but because of potential mutations, we cannot cache it until we enter the
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// render phase (where no mutations can happen anymore)
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test('computed reactivity during SSR', async () => {
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const store = {
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// initial state could be hydrated
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state: reactive({ items: null }) as any,
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// pretend to fetch some data from an api
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async fetchData() {
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this.state.items = ['hello', 'world']
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}
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}
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const getterSpy = jest.fn()
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const App = defineComponent(async () => {
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const msg = computed(() => {
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getterSpy()
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return store.state.items?.join(' ')
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})
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// If msg value is falsy then we are either in ssr context or on the client
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// and the initial state was not modified/hydrated.
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// In both cases we need to fetch data.
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if (!msg.value) await store.fetchData()
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expect(msg.value).toBe('hello world')
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return () => h('div', null, msg.value + msg.value + msg.value)
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})
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const app = createSSRApp(App)
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const html = await renderToString(app)
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expect(html).toMatch('hello world')
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// should only be called twice since access should be cached
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// during the render phase
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expect(getterSpy).toHaveBeenCalledTimes(2)
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})
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