Should I use optional() with default()?

[samuliasmala]

If I specify a default value using default(), is it unnecessary or even incorrect also specify optional()? And a related question: if I put optional() after the default() why I'm not getting the default value (please see the example below)?

> z.boolean().optional().default(true).parse()
true
> z.boolean().default(true).optional().parse()
undefined
> z.boolean().default(true).parse()
true