Force object type based on an interface

Question

I want to force a Zod type based on a TypeScript interface:

import { z } from 'zod';

interface Foo {
  id: string;
  count: number;
}

                  //👇🏻
const t = z.object<Foo>({
  count: z.number(),
  id: z.string()
})

How can I do it? The code above doesn't work.

Answer 1

You can give t the respective z.ZodType type.

const t: z.ZodType<Foo> = z.object({
  count: z.number(),
})
// Error: Property 'id' is missing in type '{ count: number; }' but required in type 'Foo'

Alternatively, you can use a helper function:

const schemaForType = <T>() => <S extends z.ZodType<T, any, any>>(arg: S) => {
  return arg;
};

schemaForType<Foo>()(
  z.object({
    id: z.string(),
    count: z.number(),
  })
);

schemaForType<Foo>()(
  z.object({
    id: z.string(),
  })
// ^^^^^^^^^^^^^^^ Error:  Property 'count' is missing in type '{ id: string; }' but required in type 'Foo'.(2345)
);

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