Parse, don't validate (2019)

Note that this basically requires your language to have ergonomic support for sum types, immutable "data classes", pattern matching.

The point is to parse the input into a structure which always upholds the predicates you care about so you don't end up continuously defensively programming in ifs and asserts.

You're describing deserialization in a strong typing language, sometimes it's not enough, ok your email went to an empty string which is useless.

With Zod: const info = z.object({ name: z.string().min(1), email: z.string().email() }

Have you seen ArkType (https://github.com/arktypeio/arktype)? Similar parse-based approach to validation with a significantly more concise definition syntax:

const info = type({ name: "string>0", email: "email" })