WebComponents connectedCallback gets mangled/minified

[xatian]

Bug report or Feature request?
Bug report?

Version (complete output of terser -V or specific git commit)
v5.12.1

Complete CLI command or minify() options used

{
  compress: {
    defaults:true,
    pure_getters:true,
  },
  ecma: 2020,
  mangle: {
    toplevel: true,
    properties: {
      keep_quoted: "strict"
    },
  },
  toplevel: true,
}

terser input

class Foo extends HTMLElement {
    public constructor () {
        super ();
    }
    public connectedCallback () {
    }
}

terser output or error

class D extends HTMLElement {
    constructor() {
        super()
    }
    ct() {}
}

Expected result

class D extends HTMLElement {
    constructor() {
        super()
    }
    connectedCallback() {}
}

connectedCallback is a reserved function name when using WebComponents yet terser seems not to care.
I tried using "reservedNames" but that seems to only work with variables and not with functions
I tried using "keep_fnames:/connectedCallback/" @ three locations (top-level, inside mangle, inside compress) --> no effect
I suppose I could fix my problem by abusing the "nameCache" but that is something I would like to avoid.

Thank you!

[xatian]

I "fixed" the issue by putting the function-name inside quotes --> like so:

class Foo extends HTMLElement {
    public constructor () {
        super ();
    }
    public "connectedCallback" () {
    }
}

This way the function-name is not touched and my problem goes away.

Still --> I think "connectedCallback" should be added to list of reserved (not to be mangled) function-names. If you don't agree you may just close this ticket.
Thank you!

[fabiosantoscode]

Hello! Thanks for reporting. The properties in this list aren't mangled by default:

https://github.com/terser/terser/blob/master/tools/domprops.js

And apparently connectedCallback isn't there indeed. A quick google of the webcomponents API revealed attributeChangedCallback which is also not present.

[FreyaHolmer]

I just lost hours due to this issue ;-; would be nice to have this properly fixed to not have others run into the same problem!