empty string now but length string later?

For a few of my schemas i have them setup like this, which means the values can be empty string:

export const telephone = type({
  international: "string",
  "local?": "string",
  "readable?": "string"
})

export const telephone = type({
  international: "string",
  "local?": "string",
  "readable?": "string"
})

But there are cases where I want to ensure the values are filled in, is there a way with arktype to specify that I want a schema to expect a value?

// i want this to throw an error because i expect the international field to be present
telephone.from({
  international: ""
})

// i want this to throw an error because i expect the international field to be present
telephone.from({
  international: ""
})

This is something that I run into a lot where the initial values stored into the DB are empty strings but when the data is updated via some controller i need to ensure the values are passed in. I dont want to duplicate all my schemas. Any recommendations?

1 Reply

ssalbdivad•2mo ago

The best way to handle a transform like this would be a custom wrapper. Here's an example of how you could implement it:

import { type } from "arktype"

function withNonEmptyStrings<t extends type.Any<object>>(t: t): t
function withNonEmptyStrings(t: type<Record<string, unknown>>) {
    return t.map(prop => {
        const stringValue = prop.value.ifExtends(type.string)
        if (!stringValue) return prop

        return {
            ...prop,
            value: stringValue.atLeastLength({
                rule: 1,
                "meta.message": "custom message"
            })
        }
    })
}

export const telephone = type({
    international: "string",
    "local?": "string",
    "readable?": "string"
})

const nonEmptyTelephone = withNonEmptyStrings(telephone)

// ArkErrors: custom message
nonEmptyTelephone.from({
    international: ""
})

import { type } from "arktype"

function withNonEmptyStrings<t extends type.Any<object>>(t: t): t
function withNonEmptyStrings(t: type<Record<string, unknown>>) {
    return t.map(prop => {
        const stringValue = prop.value.ifExtends(type.string)
        if (!stringValue) return prop

        return {
            ...prop,
            value: stringValue.atLeastLength({
                rule: 1,
                "meta.message": "custom message"
            })
        }
    })
}

export const telephone = type({
    international: "string",
    "local?": "string",
    "readable?": "string"
})

const nonEmptyTelephone = withNonEmptyStrings(telephone)

// ArkErrors: custom message
nonEmptyTelephone.from({
    international: ""
})

You could extend that map call to apply other custom transforms depending on the value type

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empty string now but length string later?

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