How can we describe a string with a length restriction?

e.g.:

type("5 < string.numeric < 7").describe("valid otp")

type("5 < string.numeric < 7").describe("valid otp")

gives the following error message: otp must be valid otp (was 3) I would expect the description to override the insertion of the current length. Is there a way to do this? Similarly, is there an easy way to remove the field name from the error, for use in inline form error display?

9 Replies

ssalbdivad•4d ago

ssalbdivad•4d ago

const otp = type("string.numeric").narrow(
    (s, ctx) =>
        s.length === 6 || ctx.reject({ expected: "a valid otp", actual: "" })
)

otp("123").toString() //?

const obj = type({
    otp: otp
})

const result = obj({ otp: "123" })

if (result instanceof type.errors) {
    console.log(result.summary)
    console.log(result[0].message)
    // .problem on the individual error omits context from path
    console.log(result[0].problem)
    console.log(result[0].expected) //?
    console.log(result[0].actual) //?
}

const otp = type("string.numeric").narrow(
    (s, ctx) =>
        s.length === 6 || ctx.reject({ expected: "a valid otp", actual: "" })
)

otp("123").toString() //?

const obj = type({
    otp: otp
})

const result = obj({ otp: "123" })

if (result instanceof type.errors) {
    console.log(result.summary)
    console.log(result[0].message)
    // .problem on the individual error omits context from path
    console.log(result[0].problem)
    console.log(result[0].expected) //?
    console.log(result[0].actual) //?
}

ssalbdivad•4d ago

I do plan to implement https://github.com/arktypeio/arktype/issues/977 soon which it looks like you've seen that would let you pass actual inline without a narrow

GitHub

Allow other error config like expected, actual, problem and `...

This would allow more granular customization e.g. of a field like password to omit actual.

francisOP•4d ago

ah, I just found that 🙂 thank you! this is helpful

ssalbdivad•4d ago

Also re: your initial expression you can also do string == 6 for exact length constraint I know it looks a little weird, but it makes more sense in the context of the other comparators 😛

francisOP•4d ago

oh, I couldn't figure that out I tried string = 6 but that failed iirc, min and max are in the docs, but not exact length

ssalbdivad•4d ago

Yeah you're probably right I'll add that

francisOP•4d ago

another quick docs note: https://arktype.io/docs/expressions has a broken link. "Narrow expressions allow you to add custom validation logic and error messages. You can read more about them in their intro section" has a link to an intro section that 404s

ssalbdivad•4d ago

Thanks for letting me know. I wish the build would fail on broken links I kind of expected it to

Gaming

Programming

How can we describe a string with a length restriction?

Did you find this page helpful?