add type truthy key

Author: huozhi

_internal/types.ts

@@ -1,7 +1,8 @@
 import * as revalidateEvents from './constants'
 import { defaultConfig } from './utils/config'
 
-export type Falsy = undefined | null | false
+type Falsy = null | undefined | false
+export type TruthyKey = Exclude<Arguments, Falsy>
 
 export type GlobalState = [
   Record<string, RevalidateCallback[]>, // EVENT_REVALIDATORS
@@ -10,7 +11,7 @@ export type GlobalState = [
   ScopedMutator, // Mutator
   (key: string, value: any, prev: any) => void, // Setter
   (key: string, callback: (current: any, prev: any) => void) => () => void, // Subscriber
-  Set<Omit<Arguments, 'null' | 'undefined'>> // Keys
+  Set<TruthyKey> // Keys
 ]
 export type FetcherResponse<Data = unknown> = Data | Promise<Data>
 export type BareFetcher<Data = unknown> = (

_internal/utils/mutate.ts

@@ -9,11 +9,11 @@ import {
   MutatorOptions,
   GlobalState,
   State,
-  Arguments
+  Arguments,
+  TruthyKey
 } from '../types'
 
-type ValidKey = Omit<Arguments, 'null' | 'undefined'>
-type KeyFilter = (key?: ValidKey) => boolean
+type KeyFilter = (key?: TruthyKey) => boolean
 
 export async function internalMutate<Data>(
   cache: Cache,
@@ -66,7 +66,7 @@ export async function internalMutate<Data>(
     return await mutateByKey(serializedKey)
   }
 
-  async function mutateByKey(_k: ValidKey): Promise<Data | undefined> {
+  async function mutateByKey(_k: TruthyKey): Promise<Data | undefined> {
     const [key] = serialize(_k)
     const [get, set] = createCacheHelper<
       Data,