wip: provide/inject

src/core/instance/inject.ts

@@ -1,12 +1,21 @@
-import { hasOwn } from 'shared/util'
 import { warn, hasSymbol, isFunction } from '../util/index'
 import { defineReactive, toggleObserving } from '../observer/index'
 import type { Component } from 'typescript/component'
+import { provide } from 'v3/apiInject'
+import { setCurrentInstance } from '../../v3/currentInstance'
 
 export function initProvide(vm: Component) {
-  const provide = vm.$options.provide
-  if (provide) {
-    vm._provided = isFunction(provide) ? provide.call(vm) : provide
+  const provideOption = vm.$options.provide
+  if (provideOption) {
+    const provided = isFunction(provideOption)
+      ? provideOption.call(vm)
+      : provideOption
+    const keys = hasSymbol ? Reflect.ownKeys(provided) : Object.keys(provided)
+    setCurrentInstance(vm)
+    for (let i = 0; i < keys.length; i++) {
+      provide(keys[i], provided[keys[i]])
+    }
+    setCurrentInstance()
   }
 }
 
@@ -47,17 +56,9 @@ export function resolveInject(
       // #6574 in case the inject object is observed...
       if (key === '__ob__') continue
       const provideKey = inject[key].from
-      let source = vm
-      while (source) {
-        if (source._provided && hasOwn(source._provided, provideKey)) {
-          result[key] = source._provided[provideKey]
-          break
-        }
-        // @ts-expect-error
-        source = source.$parent
-      }
-      if (!source) {
-        if ('default' in inject[key]) {
+      if (provideKey in vm._provided) {
+        result[key] = vm._provided[provideKey]
+      } else if ('default' in inject[key]) {
         const provideDefault = inject[key].default
         result[key] = isFunction(provideDefault)
           ? provideDefault.call(vm)
@@ -66,7 +67,6 @@ export function resolveInject(
         warn(`Injection "${key as string}" not found`, vm)
       }
     }
-    }
     return result
   }
 }

src/core/instance/lifecycle.ts

@@ -49,6 +49,7 @@ export function initLifecycle(vm: Component) {
   vm.$children = []
   vm.$refs = {}
 
+  vm._provided = parent ? parent._provided : Object.create(null)
   vm._watcher = null
   vm._inactive = null
   vm._directInactive = false

src/v3/apiInject.ts

@@ -1,3 +1,66 @@
-export function provide() {}
+import { isFunction, warn } from 'core/util'
+import { currentInstance } from './currentInstance'
 
-export function inject() {}
+export interface InjectionKey<T> extends Symbol {}
+
+export function provide<T>(key: InjectionKey<T> | string | number, value: T) {
+  if (!currentInstance) {
+    if (__DEV__) {
+      warn(`provide() can only be used inside setup().`)
+    }
+  } else {
+    let provides = currentInstance._provided
+    // by default an instance inherits its parent's provides object
+    // but when it needs to provide values of its own, it creates its
+    // own provides object using parent provides object as prototype.
+    // this way in `inject` we can simply look up injections from direct
+    // parent and let the prototype chain do the work.
+    const parentProvides =
+      currentInstance.$parent && currentInstance.$parent._provided
+    if (parentProvides === provides) {
+      provides = currentInstance._provided = Object.create(parentProvides)
+    }
+    // TS doesn't allow symbol as index type
+    provides[key as string] = value
+  }
+}
+
+export function inject<T>(key: InjectionKey<T> | string): T | undefined
+export function inject<T>(
+  key: InjectionKey<T> | string,
+  defaultValue: T,
+  treatDefaultAsFactory?: false
+): T
+export function inject<T>(
+  key: InjectionKey<T> | string,
+  defaultValue: T | (() => T),
+  treatDefaultAsFactory: true
+): T
+export function inject(
+  key: InjectionKey<any> | string,
+  defaultValue?: unknown,
+  treatDefaultAsFactory = false
+) {
+  // fallback to `currentRenderingInstance` so that this can be called in
+  // a functional component
+  const instance = currentInstance
+  if (instance) {
+    // #2400
+    // to support `app.use` plugins,
+    // fallback to appContext's `provides` if the instance is at root
+    const provides = instance.$parent && instance.$parent._provided
+
+    if (provides && (key as string | symbol) in provides) {
+      // TS doesn't allow symbol as index type
+      return provides[key as string]
+    } else if (arguments.length > 1) {
+      return treatDefaultAsFactory && isFunction(defaultValue)
+        ? defaultValue.call(instance)
+        : defaultValue
+    } else if (__DEV__) {
+      warn(`injection "${String(key)}" not found.`)
+    }
+  } else if (__DEV__) {
+    warn(`inject() can only be used inside setup() or functional components.`)
+  }
+}

src/v3/index.ts

@@ -69,6 +69,8 @@ export {
 } from 'core/observer/dep'
 export { TrackOpTypes, TriggerOpTypes } from './reactivity/operations'
 
+export { provide, inject, InjectionKey } from './apiInject'
+
 export { h } from './h'
 export { getCurrentInstance } from './currentInstance'
 export { useSlots, useAttrs } from './apiSetup'

test/unit/features/v3/apiInject.spec.ts

@@ -0,0 +1,336 @@
+import Vue from 'vue'
+import {
+  h,
+  provide,
+  inject,
+  InjectionKey,
+  ref,
+  nextTick,
+  Ref,
+  readonly,
+  reactive
+} from 'v3/index'
+
+// reference: https://vue-composition-api-rfc.netlify.com/api.html#provide-inject
+describe('api: provide/inject', () => {
+  it('string keys', () => {
+    const Provider = {
+      setup() {
+        provide('foo', 1)
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const foo = inject('foo')
+        return () => h('div', foo)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>1</div>`)
+  })
+
+  it('symbol keys', () => {
+    // also verifies InjectionKey type sync
+    const key: InjectionKey<number> = Symbol()
+
+    const Provider = {
+      setup() {
+        provide(key, 1)
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const foo = inject(key) || 1
+        return () => h('div', foo + 1)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>2</div>`)
+  })
+
+  it('default values', () => {
+    const Provider = {
+      setup() {
+        provide('foo', 'foo')
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        // default value should be ignored if value is provided
+        const foo = inject('foo', 'fooDefault')
+        // default value should be used if value is not provided
+        const bar = inject('bar', 'bar')
+        return () => h('div', foo + bar)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>foobar</div>`)
+  })
+
+  it('bound to instance', () => {
+    const Provider = {
+      setup() {
+        return () => h(Consumer)
+      }
+    }
+
+    const Consumer = {
+      name: 'Consumer',
+      inject: {
+        foo: {
+          from: 'foo',
+          default() {
+            return this!.$options.name
+          }
+        }
+      },
+      render() {
+        // @ts-ignore
+        return h('div', this.foo)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>Consumer</div>`)
+  })
+
+  it('nested providers', () => {
+    const ProviderOne = {
+      setup() {
+        provide('foo', 'foo')
+        provide('bar', 'bar')
+        return () => h(ProviderTwo)
+      }
+    }
+
+    const ProviderTwo = {
+      setup() {
+        // override parent value
+        provide('foo', 'fooOverride')
+        provide('baz', 'baz')
+        return () => h(Consumer)
+      }
+    }
+
+    const Consumer = {
+      setup() {
+        const foo = inject('foo')
+        const bar = inject('bar')
+        const baz = inject('baz')
+        return () => h('div', [foo, bar, baz].join(','))
+      }
+    }
+
+    const vm = new Vue(ProviderOne).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>fooOverride,bar,baz</div>`)
+  })
+
+  it('reactivity with refs', async () => {
+    const count = ref(1)
+
+    const Provider = {
+      setup() {
+        provide('count', count)
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const count = inject<Ref<number>>('count')!
+        return () => h('div', count.value)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>1</div>`)
+
+    count.value++
+    await nextTick()
+    expect(vm.$el.outerHTML).toBe(`<div>2</div>`)
+  })
+
+  it('reactivity with readonly refs', async () => {
+    const count = ref(1)
+
+    const Provider = {
+      setup() {
+        provide('count', readonly(count))
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const count = inject<Ref<number>>('count')!
+        // should not work
+        count.value++
+        return () => h('div', count.value)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>1</div>`)
+
+    expect(
+      `Set operation on key "value" failed: target is readonly`
+    ).toHaveBeenWarned()
+
+    // source mutation should still work
+    count.value++
+    await nextTick()
+    expect(vm.$el.outerHTML).toBe(`<div>2</div>`)
+  })
+
+  it('reactivity with objects', async () => {
+    const rootState = reactive({ count: 1 })
+
+    const Provider = {
+      setup() {
+        provide('state', rootState)
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const state = inject<typeof rootState>('state')!
+        return () => h('div', state.count)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>1</div>`)
+
+    rootState.count++
+    await nextTick()
+    expect(vm.$el.outerHTML).toBe(`<div>2</div>`)
+  })
+
+  it('reactivity with readonly objects', async () => {
+    const rootState = reactive({ count: 1 })
+
+    const Provider = {
+      setup() {
+        provide('state', readonly(rootState))
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const state = inject<typeof rootState>('state')!
+        // should not work
+        state.count++
+        return () => h('div', state.count)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div>1</div>`)
+
+    expect(
+      `Set operation on key "count" failed: target is readonly`
+    ).toHaveBeenWarned()
+
+    rootState.count++
+    await nextTick()
+    expect(vm.$el.outerHTML).toBe(`<div>2</div>`)
+  })
+
+  it('should warn unfound', () => {
+    const Provider = {
+      setup() {
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const foo = inject('foo')
+        expect(foo).toBeUndefined()
+        return () => h('div', foo)
+      }
+    }
+
+    const vm = new Vue(Provider).$mount()
+    expect(vm.$el.outerHTML).toBe(`<div></div>`)
+    expect(`injection "foo" not found.`).toHaveBeenWarned()
+  })
+
+  it('should not warn when default value is undefined', () => {
+    const Provider = {
+      setup() {
+        return () => h(Middle)
+      }
+    }
+
+    const Middle = {
+      render: () => h(Consumer)
+    }
+
+    const Consumer = {
+      setup() {
+        const foo = inject('foo', undefined)
+        return () => h('div', foo)
+      }
+    }
+
+    new Vue(Provider).$mount()
+    expect(`injection "foo" not found.`).not.toHaveBeenWarned()
+  })
+
+  // #2400
+  it('should not self-inject', () => {
+    const Comp = {
+      setup() {
+        provide('foo', 'foo')
+        const injection = inject('foo', null)
+        return () => h('div', injection)
+      }
+    }
+
+    expect(new Vue(Comp).$mount().$el.outerHTML).toBe(`<div></div>`)
+  })
+})

typescript/component.d.ts

@@ -99,7 +99,7 @@ export declare class Component {
   _vnode?: VNode | null // self root node
   _staticTrees?: Array<VNode> | null // v-once cached trees
   _hasHookEvent: boolean
-  _provided?: Record<string, any>
+  _provided: Record<string, any>
   // _virtualComponents?: { [key: string]: Component };
 
   // @v3