typebox-assert

utility function to assert and narrow a type using typebox

Install

npm install typebox-assert

Usage

Note that assertType does not just assert, it also:

• removes extra properties from value
• generates missing properties using default schema annotations
• converts type mismatches to their target type where possible

The operations are done on the provided object in a mutable manner.

For best practices, we recommend adding an $id to schemas used by assertType.

import { Type } from '@sinclair/typebox';
import { assertType } from 'typebox-assert';

const Person = Type.Object(
    {
        name: Type.String(),
        email: Type.String(),
    },
    { $id: 'Person' },
);

function createUser(data: unknown) {
    assertType(Person, data); // throws AssertionError when invalid
    db.users.insert(data); // data is narrowed to type `Person`
}