feat: onServerPrefetch (#3070)

Support equivalent of `serverPrefetch` option via Composition API.

packages/server-renderer/__tests__/render.spec.ts

@@ -14,7 +14,9 @@ import {
   watchEffect,
   createVNode,
   resolveDynamicComponent,
-  renderSlot
+  renderSlot,
+  onErrorCaptured,
+  onServerPrefetch
 } from 'vue'
 import { escapeHtml } from '@vue/shared'
 import { renderToString } from '../src/renderToString'
@@ -859,5 +861,211 @@ function testRender(type: string, render: typeof renderToString) {
         )
       ).toBe(`<div>A</div><div>B</div>`)
     })
+
+    test('onServerPrefetch', async () => {
+      const msg = Promise.resolve('hello')
+      const app = createApp({
+        setup() {
+          const message = ref('')
+          onServerPrefetch(async () => {
+            message.value = await msg
+          })
+          return {
+            message
+          }
+        },
+        render() {
+          return h('div', this.message)
+        }
+      })
+      const html = await render(app)
+      expect(html).toBe(`<div>hello</div>`)
+    })
+
+    test('multiple onServerPrefetch', async () => {
+      const msg = Promise.resolve('hello')
+      const msg2 = Promise.resolve('hi')
+      const msg3 = Promise.resolve('bonjour')
+      const app = createApp({
+        setup() {
+          const message = ref('')
+          const message2 = ref('')
+          const message3 = ref('')
+          onServerPrefetch(async () => {
+            message.value = await msg
+          })
+          onServerPrefetch(async () => {
+            message2.value = await msg2
+          })
+          onServerPrefetch(async () => {
+            message3.value = await msg3
+          })
+          return {
+            message,
+            message2,
+            message3
+          }
+        },
+        render() {
+          return h('div', `${this.message} ${this.message2} ${this.message3}`)
+        }
+      })
+      const html = await render(app)
+      expect(html).toBe(`<div>hello hi bonjour</div>`)
+    })
+
+    test('onServerPrefetch are run in parallel', async () => {
+      const first = jest.fn(() => Promise.resolve())
+      const second = jest.fn(() => Promise.resolve())
+      let checkOther = [false, false]
+      let done = [false, false]
+      const app = createApp({
+        setup() {
+          onServerPrefetch(async () => {
+            checkOther[0] = done[1]
+            await first()
+            done[0] = true
+          })
+          onServerPrefetch(async () => {
+            checkOther[1] = done[0]
+            await second()
+            done[1] = true
+          })
+        },
+        render() {
+          return h('div', '')
+        }
+      })
+      await render(app)
+      expect(first).toHaveBeenCalled()
+      expect(second).toHaveBeenCalled()
+      expect(checkOther).toEqual([false, false])
+      expect(done).toEqual([true, true])
+    })
+
+    test('onServerPrefetch with serverPrefetch option', async () => {
+      const msg = Promise.resolve('hello')
+      const msg2 = Promise.resolve('hi')
+      const app = createApp({
+        data() {
+          return {
+            message: ''
+          }
+        },
+
+        async serverPrefetch() {
+          this.message = await msg
+        },
+
+        setup() {
+          const message2 = ref('')
+          onServerPrefetch(async () => {
+            message2.value = await msg2
+          })
+          return {
+            message2
+          }
+        },
+        render() {
+          return h('div', `${this.message} ${this.message2}`)
+        }
+      })
+      const html = await render(app)
+      expect(html).toBe(`<div>hello hi</div>`)
+    })
+
+    test('mixed in serverPrefetch', async () => {
+      const msg = Promise.resolve('hello')
+      const app = createApp({
+        data() {
+          return {
+            msg: ''
+          }
+        },
+        mixins: [
+          {
+            async serverPrefetch() {
+              this.msg = await msg
+            }
+          }
+        ],
+        render() {
+          return h('div', this.msg)
+        }
+      })
+      const html = await render(app)
+      expect(html).toBe(`<div>hello</div>`)
+    })
+
+    test('many serverPrefetch', async () => {
+      const foo = Promise.resolve('foo')
+      const bar = Promise.resolve('bar')
+      const baz = Promise.resolve('baz')
+      const app = createApp({
+        data() {
+          return {
+            foo: '',
+            bar: '',
+            baz: ''
+          }
+        },
+        mixins: [
+          {
+            async serverPrefetch() {
+              this.foo = await foo
+            }
+          },
+          {
+            async serverPrefetch() {
+              this.bar = await bar
+            }
+          }
+        ],
+        async serverPrefetch() {
+          this.baz = await baz
+        },
+        render() {
+          return h('div', `${this.foo}${this.bar}${this.baz}`)
+        }
+      })
+      const html = await render(app)
+      expect(html).toBe(`<div>foobarbaz</div>`)
+    })
+
+    test('onServerPrefetch throwing error', async () => {
+      let renderError: Error | null = null
+      let capturedError: Error | null = null
+
+      const Child = {
+        setup() {
+          onServerPrefetch(async () => {
+            throw new Error('An error')
+          })
+        },
+        render() {
+          return h('span')
+        }
+      }
+
+      const app = createApp({
+        setup() {
+          onErrorCaptured(e => {
+            capturedError = e
+            return false
+          })
+        },
+        render() {
+          return h('div', h(Child))
+        }
+      })
+
+      try {
+        await render(app)
+      } catch (e) {
+        renderError = e
+      }
+      expect(renderError).toBe(null)
+      expect(((capturedError as unknown) as Error).message).toBe('An error')
+    })
   })
 }