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optional

Overview​

optional creates a codec that represents a value of a specified type or undefined. This is useful for marking properties as optional when used with optionalize.

Specification​

Accepts one argument:

  • codec: (io-ts Codec) The base codec for the type.

Returns a new codec that represents t.union([codec, t.undefined]).

Usage Example​

import * as t from 'io-ts';
import { optional } from '@api-ts/io-ts-http';

// Represents: string | undefined
const MaybeString = optional(t.string);