77 lines
1.9 KiB
TypeScript
77 lines
1.9 KiB
TypeScript
import { effect, ReactiveEffect, trigger, track } from './effect'
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import { TriggerOpTypes, TrackOpTypes } from './operations'
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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 = any> 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> = (ctx?: any) => 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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let computed: ComputedRef<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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if (!dirty) {
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dirty = true
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trigger(computed, TriggerOpTypes.SET, 'value')
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}
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}
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})
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computed = {
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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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track(computed, TrackOpTypes.GET, 'value')
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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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} as any
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return computed
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}
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