Zod implements a TypeScript model

zod-helper.ts

// Thanks https://github.com/colinhacks/zod/issues/372#issuecomment-830094773

type Implements<Model> = {
  [key in keyof Model]-?: undefined extends Model[key]
    ? null extends Model[key]
      ? z.ZodNullableType<z.ZodOptionalType<z.ZodType<Model[key]>>>
      : z.ZodOptionalType<z.ZodType<Model[key]>>
    : null extends Model[key]
    ? z.ZodNullableType<z.ZodType<Model[key]>>
    : z.ZodType<Model[key]>;
};

export function implement<Model = never>() {
  return {
    with: <
      Schema extends Implements<Model> & {
        [unknownKey in Exclude<keyof Schema, keyof Model>]: never;
      }
    >(
      schema: Schema
    ) => z.object(schema),
  };
}

// usage
export type UserModel = {
  id: string
  phoneNumber: string
  email: string | null
  name: string
  firstName: string
  companyName: string
  avatarURL: string
  createdAt: Date
  updatedAt: Date
}

export const UserModelSchema = implement<UserModel>().with({
  id: z.string(),
  phoneNumber: z.string(),
  email: z.string().email().nullable(),
  name: z.string(),
  firstName: z.string(),
  avatarURL: z.string(),
  companyName: z.string(),
  createdAt: z.date(),
  updatedAt: z.date(),
});

Force to put nullable optional or nullish when Model requires it.
Unknown properties are forbidden and cause an error 😎