88 lines
2.2 KiB
TypeScript
88 lines
2.2 KiB
TypeScript
import { effect, ReactiveEffect, effectStack } from './effect'
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import { Ref, UnwrapRef } from './ref'
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import { isFunction, NOOP } from '@vue/shared'
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export interface ComputedRef<T> extends WritableComputedRef<T> {
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readonly value: UnwrapRef<T>
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}
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export interface WritableComputedRef<T> extends Ref<T> {
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readonly effect: ReactiveEffect<T>
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}
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export type ComputedGetter<T> = () => T
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export type ComputedSetter<T> = (v: T) => void
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export interface WritableComputedOptions<T> {
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get: ComputedGetter<T>
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set: ComputedSetter<T>
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}
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export function computed<T>(getter: ComputedGetter<T>): ComputedRef<T>
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export function computed<T>(
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options: WritableComputedOptions<T>
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): WritableComputedRef<T>
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export function computed<T>(
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getterOrOptions: ComputedGetter<T> | WritableComputedOptions<T>
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) {
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let getter: ComputedGetter<T>
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let setter: ComputedSetter<T>
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if (isFunction(getterOrOptions)) {
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getter = getterOrOptions
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setter = __DEV__
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? () => {
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console.warn('Write operation failed: computed value is readonly')
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}
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: NOOP
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} else {
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getter = getterOrOptions.get
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setter = getterOrOptions.set
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}
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let dirty = true
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let value: T
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const runner = effect(getter, {
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lazy: true,
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// mark effect as computed so that it gets priority during trigger
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computed: true,
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scheduler: () => {
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dirty = true
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}
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})
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return {
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_isRef: true,
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// expose effect so computed can be stopped
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effect: runner,
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get value() {
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if (dirty) {
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value = runner()
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dirty = false
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}
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// When computed effects are accessed in a parent effect, the parent
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// should track all the dependencies the computed property has tracked.
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// This should also apply for chained computed properties.
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trackChildRun(runner)
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return value
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},
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set value(newValue: T) {
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setter(newValue)
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}
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}
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}
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function trackChildRun(childRunner: ReactiveEffect) {
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if (effectStack.length === 0) {
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return
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}
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const parentRunner = effectStack[effectStack.length - 1]
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for (let i = 0; i < childRunner.deps.length; i++) {
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const dep = childRunner.deps[i]
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if (!dep.has(parentRunner)) {
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dep.add(parentRunner)
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parentRunner.deps.push(dep)
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}
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}
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}
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