Why are policyOptions an optional argument of createPolicy?

[mbrodesser-Igalia]

https://w3c.github.io/trusted-types/dist/spec/#trustedtypepolicyfactory

A policy without options is of no use, or?

[koto]

I guess it can be used to reject every value? @otherdaniel, can we check if a 2nd argument is actually always passed to createPolicy? That seems like worthy of fixing for the API to be more ergonomic.

[mbrodesser-Igalia]

Optional is required for technical reasons:

• none of the dictionary's members can be a required member.
• https://webidl.spec.whatwg.org/#ref-for-required-dictionary-member, which contains "If the type of an argument is a dictionary type or a union type that has a dictionary type as one of its flattened member types, and that dictionary type and its ancestors have no required members, and the argument is either the final argument or is followed only by optional arguments, then the argument must be specified as optional and have a default value provided."