How to make only some props optional

[psi-4ward]

I want to derive a new Schema where some props are optional and came up with the following solution (drizzle-typebox):

import {createSelectSchema} from 'drizzle-typebox';

export const filesTbl = table(
  'files',
  {
    id: integer().primaryKey({autoIncrement: true}),
    ...tstamps,
    name: text({length: 255}).notNull(),
    contentType: text({length: 255}).notNull().default('application/octet-stream'),
    size: integer().notNull()
  },
);

export const filesSelectSchema = createSelectSchema(filesTbl);
export const filesInsertSchema = Type.Object({
  ...Type.Omit(filesSelectSchema, ['id', 'created_at', 'updated_at', 'contentType']).properties,
  contentType: Type.Optional(filesSelectSchema.properties.contentType), // We have a default value for contentType
});

So I thought about how this could be expressed in a more intuitive way like Type.Optional(fileSelectSchema, ['contentType']) so we could give a list of props which should be optional.

Is there a better way to do this? What do you think about extending the Optional() method?

Greets

[sinclairzx81]

@psi-4ward Hi, Try the following

TypeScript Link Here

import { Type } from '@sinclair/typebox'

// ----------------------------------------------------------------
// TypeScript
// ----------------------------------------------------------------

type Composite<T> = {[K in keyof T]: T[K]} & {} // replicate TB composite

type FileSelect = {
  id: string,
  created_at: number
  updated_at: number
  contentType: string
  filename: string
  description: string
}

type FileInsert = Composite<
  Omit<FileSelect, 'id' | 'created_at' | 'updated_at' | 'contentType'> &
  Partial<Pick<FileSelect, 'contentType'>>
>



// ----------------------------------------------------------------
// TypeBox
// ----------------------------------------------------------------
const FilesSelect = Type.Object({
  id: Type.String(),
  created_at: Type.Number(),
  updated_at: Type.Number(),
  contentType: Type.String(),
  filename: Type.String(),
  description: Type.String()
})

const FilesInsert = Type.Composite([
  Type.Omit(FilesSelect, ['id', 'created_at', 'updated_at', 'contentType']),
  Type.Partial(Type.Pick(FilesSelect, ['contentType'])),
])

It is generally recommended to construct types using the TB API where possible. TypeBox is mostly aligned to how you would construct the same type using TypeScript. While it is possible construct properties using the ... spread operator, working through the API generally leads to types more closely aligned to their TypeScript counterparts.

Hope this helps!
S

[psi-4ward]

Very nice! Thank you!!

function deriveInsertSchema<T extends TSchema>(t: T) {
  return Type.Composite([
    Type.Omit(t, ['id', 'createdAt', 'updatedAt', 'contentType']),
    Type.Partial(Type.Pick(t, ['contentType'])),
    Type.Optional(Type.Object({updatedAt: Type.Number({minimum: 0})}))
  ])
}

This is an example of a simple helper functions to do the modifications and looks like it works!