Optional

Optional

Validates if value is undefined or matches the expectation.

Returns: true if value is an undefined or matches expectation, else throws.

import {

check,

define,

Class,

Optional,

ValidationError,

convert,

validate,

PropTypes,

} from 'typend';

@define()

class Sandwich {

pickles?: boolean;

}

expect(convert<Sandwich>()).to.be.eql(

new Class(Sandwich, {

pickles: PropTypes.equal(Boolean).isOptional,

})

);

check<undefined | string>('foo');

check<undefined | string>(undefined);

expect(() => check<undefined | number>('foo')).to.throw(ValidationError);

validate(undefined, PropTypes.equal(String).isOptional);

validate('foo', PropTypes.instanceOf(String).isOptional);

validate('foo', new Optional(String));

expect(() => validate('foo', PropTypes.equal(Number).isOptional)).to.throw(

ValidationError

);