Function optional

optional<T>(validator): Validator<undefined | T>

Allow a validator to accept undefined inputs

Type Parameters

T
The validated type

Parameters

validator: Validator<T>

Returns Validator<undefined | T>

Example

interface Person {
    name?: string;
  }

  const isPerson = isRecordOf<Person>({ name: optional(isString) });

  isPerson({}) >>
    {
      valid: true,
      parsed: { name: undefined },
    };

  isPerson({ name: "Joel" }) >>
    {
      valid: true,
      parsed: { name: "Joel" },
    };