Removing the type guards?

Saw the note about removing check, but if it is simply safeParse().success, why can we not implement it that way in the base type? I assume this has already been tried, but if there is a problem with that, it would be helpful to know what the problem is so that I don’t accidentally reproduce the issue in my own usage.

[scotttrinh]

Wrote this little wrapper that seems to do the right thing:

function check<T>(schema: ZodSchema<T>, data: unknown): data is T {
  const parsed = schema.safeParse(data);
  return parsed.success;
}

— But still not clear why this can’t be how ZodType#check is implemented to avoid having to import this helper when using a ZodSchema

[ChristoRibeiro]

Finally I used the same way as @scotttrinh did. It works nicely with next-rest.

Full context here: https://github.com/joeltg/next-rest/issues/1

// zod-check.ts
import { ZodSchema } from "zod"

export function check<T>(schema: ZodSchema<T>) {
  function is(data: unknown): data is T {
    return schema.safeParse(data).success
  }
  return { is }
}

// pages/api/widgets/[id].ts
...
import { ZodSchema } from "zod"
import { check } from "./zod-check"

const getRequestHeaders = z.object({ accept: z.literal("application/json") })
const getRequestBody = z.void()

export default makeHandler("/api/widgets/[id]", {
  GET: {
    headers: check(getRequestHeaders).is,
    body: check(getRequestBody).is,
    exec: async ({ params }) => {
      // ... method implementation
      return {
        headers: { "content-type": "application/json" },
        body: { id: params.id, isGizmo: false },
      }
    },
  },
})

Wrote this little wrapper that seems to do the right thing:

function check<T>(schema: ZodSchema<T>, data: unknown): data is T {
  const parsed = schema.safeParse(data);
  return parsed.success;
}

— But still not clear why this can’t be how ZodType#check is implemented to avoid having to import this helper when using a ZodSchema