feat: Add extract/exclude methods to ZodEnum

deno/lib/README.md

@@ -1261,7 +1261,7 @@ type MyUnion =
   | { status: "failed"; error: Error };
 ```
 
-Such unions can be represented with the `z.discriminatedUnion` method. This enables faster evaluation, because Zod can check the _discriminator key_ (`status` in the example above) ot determine which schema should be used to parse the input. This makes parsing more efficient and lets Zod provide report friendlier errors.
+Such unions can be represented with the `z.discriminatedUnion` method. This enables faster evaluation, because Zod can check the _discriminator key_ (`status` in the example above) to determine which schema should be used to parse the input. This makes parsing more efficient and lets Zod report friendlier errors.
 
 With the basic union method the input is tested against each of the provided "options", and in the case of invalidity, issues for all the "options" are shown in the zod error. On the other hand, the discriminated union allows for selecting just one of the "options", testing against it, and showing only the issues related to this "option".
 

deno/lib/__tests__/enum.test.ts

@@ -41,3 +41,20 @@ test("error params", () => {
     expect(result.error.issues[0].message).toEqual("REQUIRED");
   }
 });
+
+test("extract/exclude", () => {
+  const foods = ["Pasta", "Pizza", "Tacos", "Burgers", "Salad"] as const;
+  const FoodEnum = z.enum(foods);
+  const ItalianEnum = FoodEnum.extract(["Pasta", "Pizza"]);
+  const UnhealthyEnum = FoodEnum.exclude(["Salad"]);
+  const EmptyFoodEnum = FoodEnum.exclude(foods);
+
+  util.assertEqual<z.infer<typeof ItalianEnum>, "Pasta" | "Pizza">(true);
+  util.assertEqual<
+    z.infer<typeof UnhealthyEnum>,
+    "Pasta" | "Pizza" | "Tacos" | "Burgers"
+  >(true);
+  // @ts-expect-error TS2344
+  util.assertEqual<typeof EmptyFoodEnum, z.ZodEnum<[]>>(true);
+  util.assertEqual<z.infer<typeof EmptyFoodEnum>, never>(true);
+});

deno/lib/types.ts

@@ -3426,6 +3426,14 @@ export interface ZodEnumDef<T extends EnumValues = EnumValues>
 
 export type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 
+export type FilterEnum<Values, ToExclude> = Values extends []
+  ? []
+  : Values extends [infer Head, ...infer Rest]
+  ? Head extends ToExclude
+    ? FilterEnum<Rest, ToExclude>
+    : [Head, ...FilterEnum<Rest, ToExclude>]
+  : never;
+
 function createZodEnum<U extends string, T extends Readonly<[U, ...U[]]>>(
   values: T,
   params?: RawCreateParams
@@ -3500,6 +3508,23 @@ export class ZodEnum<T extends [string, ...string[]]> extends ZodType<
     return enumValues as any;
   }
 
+  extract<ToExtract extends readonly [T[number], ...T[number][]]>(
+    values: ToExtract
+  ) {
+    return ZodEnum.create(values);
+  }
+
+  exclude<ToExclude extends readonly [T[number], ...T[number][]]>(
+    values: ToExclude
+  ) {
+    return ZodEnum.create(
+      this.options.filter((opt) => !values.includes(opt)) as FilterEnum<
+        T,
+        ToExclude[number]
+      >
+    );
+  }
+
   static create = createZodEnum;
 }
 

src/__tests__/enum.test.ts

@@ -40,3 +40,20 @@ test("error params", () => {
     expect(result.error.issues[0].message).toEqual("REQUIRED");
   }
 });
+
+test("extract/exclude", () => {
+  const foods = ["Pasta", "Pizza", "Tacos", "Burgers", "Salad"] as const;
+  const FoodEnum = z.enum(foods);
+  const ItalianEnum = FoodEnum.extract(["Pasta", "Pizza"]);
+  const UnhealthyEnum = FoodEnum.exclude(["Salad"]);
+  const EmptyFoodEnum = FoodEnum.exclude(foods);
+
+  util.assertEqual<z.infer<typeof ItalianEnum>, "Pasta" | "Pizza">(true);
+  util.assertEqual<
+    z.infer<typeof UnhealthyEnum>,
+    "Pasta" | "Pizza" | "Tacos" | "Burgers"
+  >(true);
+  // @ts-expect-error TS2344
+  util.assertEqual<typeof EmptyFoodEnum, z.ZodEnum<[]>>(true);
+  util.assertEqual<z.infer<typeof EmptyFoodEnum>, never>(true);
+});

src/types.ts

@@ -3426,6 +3426,14 @@ export interface ZodEnumDef<T extends EnumValues = EnumValues>
 
 export type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 
+export type FilterEnum<Values, ToExclude> = Values extends []
+  ? []
+  : Values extends [infer Head, ...infer Rest]
+  ? Head extends ToExclude
+    ? FilterEnum<Rest, ToExclude>
+    : [Head, ...FilterEnum<Rest, ToExclude>]
+  : never;
+
 function createZodEnum<U extends string, T extends Readonly<[U, ...U[]]>>(
   values: T,
   params?: RawCreateParams
@@ -3500,6 +3508,23 @@ export class ZodEnum<T extends [string, ...string[]]> extends ZodType<
     return enumValues as any;
   }
 
+  extract<ToExtract extends readonly [T[number], ...T[number][]]>(
+    values: ToExtract
+  ) {
+    return ZodEnum.create(values);
+  }
+
+  exclude<ToExclude extends readonly [T[number], ...T[number][]]>(
+    values: ToExclude
+  ) {
+    return ZodEnum.create(
+      this.options.filter((opt) => !values.includes(opt)) as FilterEnum<
+        T,
+        ToExclude[number]
+      >
+    );
+  }
+
   static create = createZodEnum;
 }