change webidl attribute to bitwise flag

[KhafraDev]

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[Renegade334]

+1. Would it be worth renaming opts parameters to flags as well, to avoid any ambiguity?

[Uzlopak]

The spec doesnt speak of Flags but extended attributes.

I think this is the wrong approach.

E.g. Clamp
https://webidl.spec.whatwg.org/#Clamp

The example would be basically:

const Clamp =  Symbol('webidl.extended-attribute.Clamp')

webidl.converters.octet = function (V) {
  // Clamped integer between 0 - 255
  if (V[Clamp] === true) {
    if (V > 255) {
      return 255
    }
    if (V < 0) {
      return 0
    }
    return V
  }
  
  // ToUint8 is basically modulo 256
  return V & 255
}

const value = new Number(257)
console.log(webidl.converters.octet(value)) // should be '1'

but:

const value = new Number(257)
value[Clamp] = true
console.log(webidl.converters.octet(octet)) // should be '255'

So I think it is expected by webidl, that we set as it clearly states attributes to the values and not pass flags to webidl functions.

[Uzlopak]

Also https://webidl.spec.whatwg.org/#annotated-types

[KhafraDev]

An extended attribute is an annotation that can appear on definitions, types as annotated types, interface members, interface mixin members, callback interface members, namespace members, dictionary members, and operation arguments, and is used to control how language bindings will handle those constructs. Extended attributes are specified with an ExtendedAttributeList, which is a square bracket enclosed, comma separated list of ExtendedAttributes.

Your approach wouldn't work, in a number of ways that would take too long to explain (and I don't have any motivation to explain). This PR is a simple refactor of moving options as an object to options as a bitwise flag.

[Uzlopak]

do we really need to check if flags is a number? cant we expect that we are smart enough to pass numbers?

[KhafraDev]

flags are optional

[Uzlopak]

I guess we cant do it closer to the spec.