operations to check subset and identity of types

I find myself with the use case to check whether a Zod type is a subset of another Zod type, and also, to help implement it, whether a Zod type is identical to another Zod type. I saw in the code earlier versions of Zod had an .is operation that has been removed.

So given:

const main = z.object({foo: z.string(), bar: z.string()});
const a = z.object({foo: z.string()});
const b = z.object({foo: z.number()});
const c = z.object({other: z.string()});

Then:

a.isSubset(main) // true, as foo is in main and the same type
b.isSubset(main) // false, as foo is not the same
c.isSubset(main) // false, as other is not present in main

This might get hairy with intersection types, though I’m not particularly concerned with this right now. Is anyone working on anything like this or is there a solution already?

[scotttrinh]

That’s a fun one! I could see something like an extends method that works like a conditional type. Nothing built in that I’m aware of, but would be happy to help point you in the right direction or review a PR to add it.

[stale[bot]]

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