Optional Fields

By default, all fields mentioned in the schema of obj are required. However, you can make a field optional explicitly.

In case you do not care how exactly the field is optional, you can use the or in combination with noting:

import { obj, str, num, or, nothing } from '@withease/contracts';

const UserWithOptionalAge = obj({
  name: str,
  age: or(num, nothing),
});

In the example above, the age field can be either a number or missing or null or undefined.

Only null

In case you expect a field to have null as a value, you can add it to the field definition as follows:

import { obj, str, num, or, val } from '@withease/contracts';

const UserWithOptionalAge = obj({
  name: str,
  age: or(num, val(null)),
});

Only undefined

If you expect a field to be missing, you can pass undefined as a value:

WARNING

In @withease/contracts, undefined as a field value is the same as a missing field. If you need to differentiate between the two, you can fallback to more powerful tools like Zod or Runtypes.

import { obj, str, num, or, val } from '@withease/contracts';

const UserWithPossibleNoAge = obj({
  name: str,
  age: or(num, val(undefined)),
});