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import { proxy, snapshot } from '../vanilla'import type { INTERNAL_Snapshot as Snapshot } from '../vanilla'
/** * proxyWithComputed * * This is to create a proxy with initial object and additional object, * which specifies getters for computed values with dependency tracking. * It also accepts optional setters for computed values. * * [Notes] * This comes with a cost and overlaps with useSnapshot. * Do not try to optimize too early. It can worsen the performance. * Measurement and comparison will be very important. * * @example * import { proxyWithComputed } from 'valtio/utils' * const state = proxyWithComputed({ *   count: 1, * }, { *   doubled: snap => snap.count * 2, // getter only *   tripled: { *     get: snap => snap.count * 3, *     set: (state, newValue) => { state.count = newValue / 3 } *   }, // with optional setter * }) */export function proxyWithComputed<T extends object, U extends object>(  initialObject: T,  computedFns: {    [K in keyof U]:      | ((snap: Snapshot<T>) => U[K])      | {          get: (snap: Snapshot<T>) => U[K]          set?: (state: T, newValue: U[K]) => void        }  }) {  ;(Object.keys(computedFns) as (keyof U)[]).forEach((key) => {    if (Object.getOwnPropertyDescriptor(initialObject, key)) {      throw new Error('object property already defined')    }    const computedFn = computedFns[key]    const { get, set } = (      typeof computedFn === 'function' ? { get: computedFn } : computedFn    ) as {      get: (snap: Snapshot<T>) => U[typeof key]      set?: (state: T, newValue: U[typeof key]) => void    }    const desc: PropertyDescriptor = {}    desc.get = () => get(snapshot(proxyObject))    if (set) {      desc.set = (newValue) => set(proxyObject, newValue)    }    Object.defineProperty(initialObject, key, desc)  })  const proxyObject = proxy(initialObject) as T & U  return proxyObject}