Unable to morph object values with default

[TizzySaurus]

Report a bug

It seems it's currently impossible to morph and object value that has a default.

🔎 Search Terms

object default, morph default

🧩 Context

• ArkType version: 2.0.0-beta.5
• TypeScript version (5.1+):
• Other context you think may be relevant (JS flavor, OS, etc.):

🧑‍💻 Repro

const t = type({
    foo: ["'on' | 'off' = 'on'", "=>", v => v === "on"]
});

The types indicate that this is valid, however at runtime it produces the following error:

Default values must be specified on objects like { isAdmin: 'boolean = false' }

It's not possible to use the syntax off foo: "'on'|'off' = 'on'" since I want to morph the type. The following attempts also raise the same error:

const t1 = type({
    foo: type("'on' | 'off' = 'on'").pipe(v => v === "on")
});

const t2 = type({
    foo: type(["'on' | 'off' = 'on'", "=>", v => v === "on"])
});

[ssalbdivad]

Hmm, I think it occurred to me this wouldn't be possible, but I should handle it more clearly when someone tries to do it.

It doesn't really make sense to set a default value then apply a morph. You should just have the default value be whatever the output of your morph called on that default value would be and save yourself the extra computation.

[ssalbdivad]

I am considering removing the restriction on shallow default values/optional keys though which would make this stuff more flexible. For now though, I'm not going to address this individual case since it feels like an anti-pattern.