A
arktype•2w ago
nateiler

Reference another schema type as default?

Hello, I'm relatively new to Arktype. I've managed to figure out most of our Zod migration, however I have a couple scenarios where I would like to reference other types as default values -or- compose a 'computed' property. In this scenario I'd like to use the provided 'createdAt' value as the default 'modifiedAt' value: 
import { type } from 'arktype';

const UserSchema = type({
  firstName: type("string"),
  lastName: type("string"),
  createdAt: type("string.date.iso.parse"),
  modifiedAt: type("string.date.iso.parse").default(// -> default to createdAt)
})
import { type } from 'arktype';

const UserSchema = type({
  firstName: type("string"),
  lastName: type("string"),
  createdAt: type("string.date.iso.parse"),
  modifiedAt: type("string.date.iso.parse").default(// -> default to createdAt)
})
And in this scenario, I'm doing some parsing prior to return an API payload. I would like to compose a type based off two other types: 
const UserSchema = type({
  firstName: type("string"),
  lastName: type("string"),
  name: type("string").default(// -> reference firstName and lastName),
})
const UserSchema = type({
  firstName: type("string"),
  lastName: type("string"),
  name: type("string").default(// -> reference firstName and lastName),
})
Note : these are simplified examples Both seem somewhat related, but I haven't figured out how or if it's possible to accomplish these.
2 Replies
ssalbdivad
ssalbdivad•2w ago
You can morph the top-level object and transform the value directly: 
const UserSchema = type({
    firstName: "string",
    lastName: "string",
    "name?": "string"
}).pipe(user =>
    user.name ? user : { ...user, name: `${user.firstName} ${user.lastName}` }
)
const UserSchema = type({
    firstName: "string",
    lastName: "string",
    "name?": "string"
}).pipe(user =>
    user.name ? user : { ...user, name: `${user.firstName} ${user.lastName}` }
)
nateiler
nateilerOP•2w ago
Makes perfect sense! Thanks!

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