fix(types): JSONParsed supports interface and Date etc. (#1853)

* fix(types): `JSONParsed` supports interface and `Date` etc. * denoify * supports bigint as never * denoify
honojs · Jan 2, 2024 · 571c284 · 571c284
1 parent d5d2e23
commit 571c284
Show file tree

Hide file tree

Showing 3 changed files with 95 additions and 6 deletions.
diff --git a/deno_dist/utils/types.ts b/deno_dist/utils/types.ts
@@ -27,9 +27,18 @@ export type JSONPrimitive = string | boolean | number | null | undefined
 export type JSONArray = (JSONPrimitive | JSONObject | JSONArray)[]
 export type JSONObject = { [key: string]: JSONPrimitive | JSONArray | JSONObject | object }
 export type JSONValue = JSONObject | JSONArray | JSONPrimitive
-export type JSONParsed<T> = {
- [k in keyof T]: T[k] extends JSONValue ? T[k] : string
-}
+// Non-JSON values such as `Date` implement `.toJSON()`, so they can be transformed to a value assignable to `JSONObject`:
+export type JSONParsed<T> = T extends { toJSON(): infer J }
+ ? (() => J) extends () => JSONObject
+ ? J
+ : JSONParsed<J>
+ : T extends JSONPrimitive
+ ? T
+ : T extends Array<infer U>
+ ? Array<JSONParsed<U>>
+ : T extends object
+ ? { [K in keyof T]: JSONParsed<T[K]> }
+ : never
 
 export type InterfaceToType<T> = T extends Function ? T : { [K in keyof T]: InterfaceToType<T[K]> }
 

diff --git a/src/utils/types.test.ts b/src/utils/types.test.ts
@@ -0,0 +1,71 @@
+import type { Equal, Expect, JSONParsed } from './types'
+
+describe('JSONParsed', () => {
+ enum SampleEnum {
+ Value1 = 'value1',
+ Value2 = 'value2',
+ }
+
+ interface Meta {
+ metadata: {
+ href: string
+ sampleEnum: SampleEnum
+ }
+ }
+
+ interface SampleInterface {
+ someMeta: Meta
+ }
+
+ type SampleType = {
+ someMeta: Meta
+ }
+
+ it('Should parse a complex type', () => {
+ const sample: JSONParsed<SampleType> = {
+ someMeta: {
+ metadata: {
+ href: '',
+ sampleEnum: SampleEnum.Value1,
+ },
+ },
+ }
+ expectTypeOf(sample).toEqualTypeOf<SampleType>()
+ })
+
+ it('Should parse a complex interface', () => {
+ const sample: JSONParsed<SampleInterface> = {
+ someMeta: {
+ metadata: {
+ href: '',
+ sampleEnum: SampleEnum.Value1,
+ },
+ },
+ }
+ expectTypeOf(sample).toEqualTypeOf<SampleInterface>()
+ })
+
+ it('Should convert Date to string', () => {
+ type Post = {
+ datetime: Date
+ }
+ type Expected = {
+ datetime: string
+ }
+ type Actual = JSONParsed<Post>
+ // eslint-disable-next-line @typescript-eslint/no-unused-vars
+ type verify = Expect<Equal<Expected, Actual>>
+ })
+
+ it('Should convert bigint to never', () => {
+ type Post = {
+ num: bigint
+ }
+ type Expected = {
+ num: never
+ }
+ type Actual = JSONParsed<Post>
+ // eslint-disable-next-line @typescript-eslint/no-unused-vars
+ type verify = Expect<Equal<Expected, Actual>>
+ })
+})
diff --git a/src/utils/types.ts b/src/utils/types.ts
@@ -27,9 +27,18 @@ export type JSONPrimitive = string | boolean | number | null | undefined
 export type JSONArray = (JSONPrimitive | JSONObject | JSONArray)[]
 export type JSONObject = { [key: string]: JSONPrimitive | JSONArray | JSONObject | object }
 export type JSONValue = JSONObject | JSONArray | JSONPrimitive
-export type JSONParsed<T> = {
- [k in keyof T]: T[k] extends JSONValue ? T[k] : string
-}
+// Non-JSON values such as `Date` implement `.toJSON()`, so they can be transformed to a value assignable to `JSONObject`:
+export type JSONParsed<T> = T extends { toJSON(): infer J }
+ ? (() => J) extends () => JSONObject
+ ? J
+ : JSONParsed<J>
+ : T extends JSONPrimitive
+ ? T
+ : T extends Array<infer U>
+ ? Array<JSONParsed<U>>
+ : T extends object
+ ? { [K in keyof T]: JSONParsed<T[K]> }
+ : never
 
 export type InterfaceToType<T> = T extends Function ? T : { [K in keyof T]: InterfaceToType<T[K]> }