Add index signature for passthrough

deno/lib/__tests__/object.test.ts

@@ -123,8 +123,8 @@ test("catchall inference", () => {
     .catchall(z.number());
 
   const d1 = o1.parse({ first: "asdf", num: 1243 });
-  util.assertEqual<number, typeof d1["asdf"]>(true);
-  util.assertEqual<string, typeof d1["first"]>(true);
+  util.assertEqual<number, (typeof d1)["asdf"]>(true);
+  util.assertEqual<string, (typeof d1)["first"]>(true);
 });
 
 test("catchall overrides strict", () => {
@@ -442,3 +442,12 @@ test("extend() should have power to override existing key", () => {
     { firstName: string; lastName: number }
   >(true);
 });
+
+test("passthrough index signature", () => {
+  const a = z.object({ a: z.string() });
+  type a = z.infer<typeof a>;
+  util.assertEqual<{ a: string }, a>(true);
+  const b = a.passthrough();
+  type b = z.infer<typeof b>;
+  util.assertEqual<{ a: string } & { [k: string]: unknown }, b>(true);
+});

deno/lib/types.ts

@@ -2127,11 +2127,14 @@ export type baseObjectOutputType<Shape extends ZodRawShape> =
 
 export type objectOutputType<
   Shape extends ZodRawShape,
-  Catchall extends ZodTypeAny
+  Catchall extends ZodTypeAny,
+  UnknownKeys extends UnknownKeysParam
 > = ZodTypeAny extends Catchall
-  ? objectUtil.flatten<baseObjectOutputType<Shape>>
+  ? objectUtil.flatten<baseObjectOutputType<Shape>> & Passthrough<UnknownKeys>
   : objectUtil.flatten<
-      baseObjectOutputType<Shape> & { [k: string]: Catchall["_output"] }
+      baseObjectOutputType<Shape> & {
+        [k: string]: Catchall["_output"];
+      } & Passthrough<UnknownKeys>
     >;
 
 export type baseObjectInputType<Shape extends ZodRawShape> = objectUtil.flatten<
@@ -2140,13 +2143,19 @@ export type baseObjectInputType<Shape extends ZodRawShape> = objectUtil.flatten<
   }>
 >;
 
+export type Passthrough<UnknownKeys extends UnknownKeysParam> =
+  UnknownKeys extends "passthrough" ? { [k: string]: unknown } : unknown;
+
 export type objectInputType<
   Shape extends ZodRawShape,
-  Catchall extends ZodTypeAny
+  Catchall extends ZodTypeAny,
+  UnknownKeys extends UnknownKeysParam
 > = ZodTypeAny extends Catchall
-  ? baseObjectInputType<Shape>
+  ? baseObjectInputType<Shape> & Passthrough<UnknownKeys>
   : objectUtil.flatten<
-      baseObjectInputType<Shape> & { [k: string]: Catchall["_input"] }
+      baseObjectInputType<Shape> & {
+        [k: string]: Catchall["_input"];
+      } & Passthrough<UnknownKeys>
     >;
 
 export type deoptional<T extends ZodTypeAny> = T extends ZodOptional<infer U>
@@ -2198,8 +2207,8 @@ export class ZodObject<
   T extends ZodRawShape,
   UnknownKeys extends UnknownKeysParam = UnknownKeysParam,
   Catchall extends ZodTypeAny = ZodTypeAny,
-  Output = objectOutputType<T, Catchall>,
-  Input = objectInputType<T, Catchall>
+  Output = objectOutputType<T, Catchall, UnknownKeys>,
+  Input = objectInputType<T, Catchall, UnknownKeys>
 > extends ZodType<Output, ZodObjectDef<T, UnknownKeys, Catchall>, Input> {
   private _cached: { shape: T; keys: string[] } | null = null;
 

playground.ts

@@ -1,4 +1,4 @@
 import { z } from "./src";
-const px = z.custom<`${number}px`>((val) => /^\d+px$/.test(val as string));
-px.parse("100px"); // pass
-px.parse("100vw"); // fail
+
+const a = z.object({ a: z.string() }).passthrough();
+type a = z.infer<typeof a>;

src/__tests__/object.test.ts

@@ -122,8 +122,8 @@ test("catchall inference", () => {
     .catchall(z.number());
 
   const d1 = o1.parse({ first: "asdf", num: 1243 });
-  util.assertEqual<number, typeof d1["asdf"]>(true);
-  util.assertEqual<string, typeof d1["first"]>(true);
+  util.assertEqual<number, (typeof d1)["asdf"]>(true);
+  util.assertEqual<string, (typeof d1)["first"]>(true);
 });
 
 test("catchall overrides strict", () => {
@@ -441,3 +441,12 @@ test("extend() should have power to override existing key", () => {
     { firstName: string; lastName: number }
   >(true);
 });
+
+test("passthrough index signature", () => {
+  const a = z.object({ a: z.string() });
+  type a = z.infer<typeof a>;
+  util.assertEqual<{ a: string }, a>(true);
+  const b = a.passthrough();
+  type b = z.infer<typeof b>;
+  util.assertEqual<{ a: string } & { [k: string]: unknown }, b>(true);
+});

src/types.ts

@@ -2127,11 +2127,14 @@ export type baseObjectOutputType<Shape extends ZodRawShape> =
 
 export type objectOutputType<
   Shape extends ZodRawShape,
-  Catchall extends ZodTypeAny
+  Catchall extends ZodTypeAny,
+  UnknownKeys extends UnknownKeysParam
 > = ZodTypeAny extends Catchall
-  ? objectUtil.flatten<baseObjectOutputType<Shape>>
+  ? objectUtil.flatten<baseObjectOutputType<Shape>> & Passthrough<UnknownKeys>
   : objectUtil.flatten<
-      baseObjectOutputType<Shape> & { [k: string]: Catchall["_output"] }
+      baseObjectOutputType<Shape> & {
+        [k: string]: Catchall["_output"];
+      } & Passthrough<UnknownKeys>
     >;
 
 export type baseObjectInputType<Shape extends ZodRawShape> = objectUtil.flatten<
@@ -2140,13 +2143,19 @@ export type baseObjectInputType<Shape extends ZodRawShape> = objectUtil.flatten<
   }>
 >;
 
+export type Passthrough<UnknownKeys extends UnknownKeysParam> =
+  UnknownKeys extends "passthrough" ? { [k: string]: unknown } : unknown;
+
 export type objectInputType<
   Shape extends ZodRawShape,
-  Catchall extends ZodTypeAny
+  Catchall extends ZodTypeAny,
+  UnknownKeys extends UnknownKeysParam
 > = ZodTypeAny extends Catchall
-  ? baseObjectInputType<Shape>
+  ? baseObjectInputType<Shape> & Passthrough<UnknownKeys>
   : objectUtil.flatten<
-      baseObjectInputType<Shape> & { [k: string]: Catchall["_input"] }
+      baseObjectInputType<Shape> & {
+        [k: string]: Catchall["_input"];
+      } & Passthrough<UnknownKeys>
     >;
 
 export type deoptional<T extends ZodTypeAny> = T extends ZodOptional<infer U>
@@ -2198,8 +2207,8 @@ export class ZodObject<
   T extends ZodRawShape,
   UnknownKeys extends UnknownKeysParam = UnknownKeysParam,
   Catchall extends ZodTypeAny = ZodTypeAny,
-  Output = objectOutputType<T, Catchall>,
-  Input = objectInputType<T, Catchall>
+  Output = objectOutputType<T, Catchall, UnknownKeys>,
+  Input = objectInputType<T, Catchall, UnknownKeys>
 > extends ZodType<Output, ZodObjectDef<T, UnknownKeys, Catchall>, Input> {
   private _cached: { shape: T; keys: string[] } | null = null;