feat: type parameter on get

Author: ph-fritsche

README.md

@@ -80,6 +80,12 @@ You can also make a component use its own local cache:
   get('indexKeyForValue')
 ```
 
+In TypeScript you can declare the data type you get:
+```ts
+  const { get } = useCached()
+  get<number>('indexKeyForValue')
+```
+
 #### Get multiple values
 
 ```js

src/index.ts

@@ -1,2 +1,4 @@
 export * from './useCached'
 export { CacheProvider } from './context'
+export type { cachedObj } from './shared'
+export type { getReturn as cachedGet } from './methods'

src/methods/get.ts

@@ -1,24 +1,27 @@
 import { getMany } from 'idb-keyval'
 import { addListener, cachedObj, debugLog, dispatch, expire, reactCache, setProperty, verifyEntry } from '../shared'
 
-type valueTypes = {
-    data: cachedObj['data'],
-    obj: cachedObj & {valid: boolean},
+type returnTypes<T> = {
+    data: cachedObj<T>['data'],
+    obj: cachedObj<T> & {valid: boolean},
 }
 
 export type getValue<
-    T extends keyof valueTypes | undefined
-> = (T extends keyof valueTypes ? valueTypes[T] : valueTypes['data']) | undefined
+    R extends keyof returnTypes<T> | undefined,
+    T extends unknown = unknown
+> = (R extends keyof returnTypes<T> ? returnTypes<T>[R] : returnTypes<T>['data']) | undefined
 
 export type getReturn<
     K extends string | string[],
-    T extends keyof valueTypes | undefined,
+    R extends keyof returnTypes<T> | undefined,
+    T extends unknown = unknown,
 > = K extends string[]
-    ? { [k in K[number]]: getValue<T> }
-    : getValue<T>
+    ? { [k in K[number]]: getValue<R, T> }
+    : getValue<R, T>
 
 export function get<
     K extends string | string[],
+    T extends unknown = unknown,
 >(
     cache: reactCache,
     store: Parameters<typeof getMany>[1],
@@ -28,10 +31,11 @@ export function get<
     loader?: (missingKeys: string[]) => Promise<void>,
     expire?: expire | undefined,
     returnType?: undefined,
-): getReturn<K, undefined>;
+): getReturn<K, undefined, T>;
 export function get<
     K extends string | string[],
-    T extends keyof valueTypes | undefined,
+    R extends keyof returnTypes<T> | undefined,
+    T extends unknown = unknown,
 >(
     cache: reactCache,
     store: Parameters<typeof getMany>[1],
@@ -40,12 +44,13 @@ export function get<
     keyOrKeys: K,
     loader?: (missingKeys: string[]) => Promise<void>,
     expire?: expire,
-    returnType?: T,
-): getReturn<K, T>;
+    returnType?: R,
+): getReturn<K, R, T>;
 
 export function get<
     K extends string | string[],
-    T extends keyof valueTypes | undefined,
+    R extends keyof returnTypes<T> | undefined,
+    T extends unknown = unknown,
 >(
     cache: reactCache,
     store: Parameters<typeof getMany>[1],
@@ -54,13 +59,13 @@ export function get<
     keyOrKeys: K,
     loader?: (missingKeys: string[]) => Promise<void>,
     expire?: expire,
-    returnType?: T,
-): getReturn<K, T> {
+    returnType?: R,
+): getReturn<K, R, T> {
     const keys = (Array.isArray(keyOrKeys) ? keyOrKeys : [keyOrKeys]) as string[]
 
     addListener(cache, keys, id, rerender)
 
-    const values: Record<string, getValue<T>> = {}
+    const values: Record<string, getValue<R, T>> = {}
     const missing: string[] = []
 
     keys.forEach(key => {
@@ -69,9 +74,9 @@ export function get<
             missing.push(key)
         }
         if (returnType === 'obj') {
-            values[key] = (cache[key].obj ? { ...cache[key].obj, valid } : undefined) as getValue<T>
+            values[key] = (cache[key].obj ? { ...cache[key].obj, valid } : undefined) as getValue<R, T>
         } else {
-            values[key] = cache[key].obj?.data as getValue<T>
+            values[key] = cache[key].obj?.data as getValue<R, T>
         }
     })
 
@@ -119,5 +124,5 @@ export function get<
         })
     }
 
-    return (Array.isArray(keyOrKeys) ? values : values[keys[0]]) as getReturn<K, T>
+    return (Array.isArray(keyOrKeys) ? values : values[keys[0]]) as getReturn<K, R, T>
 }

src/methods/index.ts

@@ -5,6 +5,8 @@ import { del } from './del'
 import { get, getReturn } from './get'
 import { set } from './set'
 
+export type { getReturn }
+
 declare function boundClear(
     expire?: expire,
 ): Promise<void>;
@@ -15,13 +17,14 @@ declare function boundDel(
 
 declare function boundGet<
     K extends Parameters<typeof get>[4],
-    T extends Parameters<typeof get>[7],
+    R extends Parameters<typeof get>[7],
+    T extends unknown = unknown,
 >(
     keyOrKeys: K,
     loader?: Parameters<typeof get>[5],
     expire?: Parameters<typeof get>[6],
-    returnType?: T,
-): getReturn<K, T>;
+    returnType?: R,
+): getReturn<K, R, T>;
 
 declare function boundSet(
     recordData: Record<string, cachedObj['data']>,

src/shared/cache.ts

@@ -1,15 +1,15 @@
-export interface reactCacheEntry {
-    promise?: Promise<cachedObj | undefined>,
-    obj?: cachedObj,
+export interface reactCacheEntry<T extends unknown = unknown> {
+    promise?: Promise<cachedObj<T> | undefined>,
+    obj?: cachedObj<T>,
     listeners?: Record<string, () => void>,
 }
 
 export type reactCache = Record<string, reactCacheEntry>
 
 export type expire = number | ((obj: cachedObj) => boolean)
 
-export interface cachedObj {
-    data: unknown,
+export type cachedObj<T extends unknown = unknown> = {
+    data: T,
     meta: {
         date?: Date | string,
         [k: string]: unknown,