Zod Tutorial (10 exercises)
Problem

Be Specific with Allowed Types

We're validating forms again in this example.

This time Form has a privacyLevel that can be two types: either private or public:

const Form = z.object({
  repoName: z.string(),
  privacyLevel: z.string(),
});

If we were going to represent this in TypeScript, we would write:

type PrivacyLevel = 'private' | 'public'

Of course, we could use a boolean here, but we may need to add more privacy levels in the future. It's often safer to use a union type or an enum here as well.

Challenge

The first test we have currently fails because our validateFormInput function allows for strings other than "private" or "public":

it("Should fail if an invalid privacyLevel passed", async () => {
  expect(() =>
    validateFormInput({
      repoName: "mattpocock",
      privacyLevel: "something-not-allowed",
    }),
  ).toThrowError();
});

Your challenge is to find an API in Zod that allows you to be more specific with the types of strings that can be passed into the validator function.

Code

logo-github

zod-tutorial

/src/07-union.problem.ts

Transcript

Matt Pocock: Another day, another form. We are validating form inputs again, this time on a repoName, except that we've got this privacyLevel here. This privacyLevel, it's actually really only two types. It's going to be either private or public here.

If you were to represent this in TypeScript, you would say, "type PrivacyLevel = 'private' | 'public'." Of course, we could use a Boolean here, but we might need to add more privacy levels in the future. It's often safer to use a union type here or an enum.

Your challenge here then is we can see that the tests are not working. If we say "yarn e 07," then we can see that this is failing because you're not allowed to pass in something-not-allowed here. We need to restrict that somehow. Your challenge is to find an API in Zod that allows you to be more specific with the types of strings that you can pass in here.