[BUG] class accessors are not configurable

When defining a class in ES6, like

class Foo {
  get bar() {...}
  set bar(value) {...}
}

the accessors are configurable.

However, Buble output uses Object.defineProperties to create the accessors, and by default Object.defineProperties sets configurable to false.

This makes some code, like the following utility function that I use in non-Buble projects fail:

function makeAccessorsEnumerable(object) {
    const props = Object.getOwnPropertyNames(object)
    for (let l=props.length, i=0; i<l; i+=1) {
        const prop = props[i]
        const descriptor = Object.getOwnPropertyDescriptor(object, prop)
        console.log('descriptor for '+prop+':', descriptor)
        if (descriptor && (descriptor.set || descriptor.get)) {
            descriptor.enumerable = true
            Object.defineProperty(object, prop, descriptor)
        }
    }
}

To reproduce the bug, you can paste and run the following in Chrome console:

class Foo {
  get bar() {return this.v}
  set bar(v) {this.v = v}
}

makeAccessorsEnumerable(Foo.prototype) // it works, so far so good!

Object.defineProperties(Foo.prototype, {
  lorem: {set: function(v) {this.l = v}, get: function() {return this.l}}
})

makeAccessorsEnumerable(Foo.prototype) // ERROR, because lorem is not configurable!

function makeAccessorsEnumerable(object) {
    const props = Object.getOwnPropertyNames(object)
    for (let l=props.length, i=0; i<l; i+=1) {
        const prop = props[i]
        const descriptor = Object.getOwnPropertyDescriptor(object, prop)
        console.log('descriptor for '+prop+':', descriptor)
        if (descriptor && (descriptor.set || descriptor.get)) {
            descriptor.enumerable = true
            Object.defineProperty(object, prop, descriptor)
        }
    }
}

The same applies to static accessors.

changed title from [Bug] Wrong property descriptors for class accessors to [BUG] class accessors are not configurable

changed the description

mentioned in merge request !121 (closed)

This will be fixed in https://gitlab.com/Rich-Harris/buble/merge_requests/121.

Would it be worth changing from this format,

Foo.prototype.bar = function() {...}
Foo.prototype.baz = function() {...}

format to

Object.defineProperties(Foo.prototype, {
  bar: {configurable: true, writable: true, value: function() {...}}
  baz: {configurable: true, writable: true, value: function() {...}}
})

to be spec compliant?

mentioned in issue #213

changed title from [BUG] class accessors are not configurable to [BUG] class accessors are not configurable or enumerable

changed title from [BUG] class accessors are not configurable or enumerable to [BUG] class accessors are not configurable