Zod•5w ago

unnreaal - tsconst schema = z.coerce.string()....

const schema = z.coerce.string().optional();

// type Schema = string | undefined;
type Schema = z.infer<typeof schema>;

const schema = z.coerce.string().optional();

// type Schema = string | undefined;
type Schema = z.infer<typeof schema>;

But z.coerce.string() will always cast the value to a string, why not just string instead of string | undefined?

24 Replies

Scott Trinh•5w ago

Infer is the input type. z.output gives the output type

unnreaalOP•5w ago

still the same with z.output

Scott Trinh•5w ago

Oh yeah, I guess it would be that type. Optional doesn't make sense here since coerce swallows undefined. 🤔

unnreaalOP•5w ago

its a type error no?

Scott Trinh•5w ago

Well... sure, I could see that, but really optional and nullable are just not really meaningful for coerce types. Same for union, really Is there something specific you're intending to mean by making it optional? It already accepts undefined as an input.

unnreaalOP•5w ago

no, i mean that the type (z.output) is wrong

Scott Trinh•5w ago

It's only wrong because .optional makes everything | undefined, but optional doesn't mean anything for z.coerce schemas, so it's "right" but only technically right.

unnreaalOP•5w ago

yes bro, i know the | undefined doesn't mean anything for z.coerce schemas i mean that the type is completely wrong

Scott Trinh•5w ago

for instance, this is also supported, but doesn't work:

const schema = z.union([z.coerce.string(), z.coerce.number()]);
type Schema = z.output<typeof schema>;
// string | number

const schema = z.union([z.coerce.string(), z.coerce.number()]);
type Schema = z.output<typeof schema>;
// string | number

In actuality, it's always string at runtime.

unnreaalOP•5w ago

const user = z.object({
  name: z.coerce.string().optional(),
});

// { name: string | undefined; }
type User = z.output<user>;

const user = z.object({
  name: z.coerce.string().optional(),
});

// { name: string | undefined; }
type User = z.output<user>;

Scott Trinh•5w ago

I mean that .optional should not be an option for coerce schemas.

unnreaalOP•5w ago

but the name is always a string here so zod should throw an error warning the optional can not (or is unnecessary) be used with coerce schemas

Scott Trinh•5w ago

Nope: this is { name: string; }

Scott Trinh•5w ago

https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBAbzgLzgXzgMyhEcBEyEAJvgNwBQFAxhAHYDO8ArgwKZRwC8KAdBACMAVm2owAFAgpw4dAIYg2ALj60O1NryZRgdAObiAlABoKaQ5QowAnmDZwAqu049k-ZjDAeAPDbsRMOFYOAD5KAHpwmTgAPQB+IA

TS Playground - An online editor for exploring TypeScript and JavaS...

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Scott Trinh•5w ago

it should just not allow you to .optional() on a coerce schema.

unnreaalOP•5w ago

nop im sure it isnt it is { name?: string | undefined; } try yourself

Scott Trinh•5w ago

no, your original (without the .optional) is string

unnreaalOP•5w ago

bro, i edited the message (before you send the playground link)

Scott Trinh•5w ago

yep! don't use optional for coerce schemas.

unnreaalOP•5w ago

zod should throw an error or at least warn users

Scott Trinh•5w ago

yes it should just not include an .optional method. but it does for now, so just avoid it until we fix that.

unnreaalOP•5w ago

.optional is in ZodType, no?

Scott Trinh•5w ago

it is! we'll need to fix that. in the meantime, do not: 1. Use optional, nullish, or nullable with z.coerce schemas 2. Use z.coerce schemas in a z.union 3. Probably other stuff.

Scott Trinh•5w ago

I filed an issue: https://github.com/colinhacks/zod/issues/3837

GitHub

We should not allow optional, nullish, or nullable on `z.coer...

Since z.coerce.* schemas will always return the primitive, even if you pass undefined or null, we should disallow this. Also, things like z.union([z.coerce.string(), z.coerce.number()]) will always...

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unnreaal - tsconst schema = z.coerce.string()....