fixup Draft<T>

immerjs · Dec 18, 2018 · 8ce6fd4 · 8ce6fd4
1 parent 738bba5
commit 8ce6fd4
Showing 1 changed file with 13 additions and 19 deletions.
diff --git a/src/immer.d.ts b/src/immer.d.ts
@@ -15,32 +15,26 @@ type AtomicObject =
     | Number
     | String
 
-type IsTuple<T extends ReadonlyArray<any>> = T extends never[]
-    ? true
-    : T extends ReadonlyArray<infer U>
-    ? (U[] extends T ? false : true)
-    : never
-
-export type DraftObject<T extends object> = T extends AtomicObject
-    ? T
-    : {-readonly [P in keyof T]: Draft<T[P]>}
-
-export type DraftArray<T, U = keyof T> = {[P in U]: Array<T>}[U]
+export type DraftArray<T extends ReadonlyArray<any>> = {
+    [P in Exclude<keyof T, ArrayMethod>]: Draft<T[P]>
+}[Exclude<keyof T, ArrayMethod>][]
 
 type ArrayMethod = Exclude<keyof [], number>
 
-export type DraftTuple<T extends any[]> = Id<
+export type DraftTuple<T extends ReadonlyArray<any>> = Id<
     {[P in keyof T]: P extends ArrayMethod ? never : Draft<T[P]>}
 >
 
-export type Draft<T> = T extends any[]
-    ? IsTuple<T> extends true
-        ? DraftTuple<T>
-        : DraftArray<T[number]>
-    : T extends ReadonlyArray<any>
-    ? DraftArray<T[number]>
+export type Draft<T> = T extends ReadonlyArray<any>
+    ? T extends never[]
+        ? T
+        : T[number][] extends T
+        ? DraftArray<T>
+        : DraftTuple<T>
+    : T extends AtomicObject
+    ? T
     : T extends object
-    ? DraftObject<T>
+    ? {-readonly [P in keyof T]: Draft<T[P]>}
     : T
 
 export interface Patch {