FromSchema returns unknown (code example)

[nabilfreeman]

Code to reproduce:

import { JSONSchema, FromSchema } from 'json-schema-to-ts';

export const TestSchema: JSONSchema = {
    type: 'object',
    properties: {
        id: { type: 'number' },
    },
    additionalProperties: false,
} as const;

export type TestColumns = FromSchema<typeof TestSchema>;

// TestColumns is type `unknown`

TS version: 5.0.4 Library version: ^2.9.1

Also tried downgrading to 2.8.2

A bit sad as I was very excited to use this library! 🥺

[nabilfreeman]

I figured this out last night - It's because I typed TestSchema as JSONSchema instead of using satisfies.

Here is the working code:

import { JSONSchema, FromSchema } from 'json-schema-to-ts';

export const TestSchema = {
    type: 'object',
    properties: {
        id: { type: 'number' },
    },
    additionalProperties: false,
} as const satisfies JSONSchema;

export type TestColumns = FromSchema<typeof TestSchema>;

// TestColumns is type `{ id: number }`

[nabilfreeman]

Closing. I think this should help unblock somebody searching for "unknown" in the future. 👍

[ThomasAribart]

Nice !