1842565 - Class methods are not defined in the constructor if the class has been extended from HTMLElement inside webextension `content_script`

Status: RESOLVED DUPLICATE of bug 1820521

(WebExtensions :: Untriaged, defect)

Description

[Alex]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/116.0

Steps to reproduce:

Create web extension with the content script which should create custom element:

class ManualApp extends HTMLElement {
  constructor() {
    super();
    this._log('hello world') // TypeError: this._log is not a function
  }

  _log(str) {
    console.log(str);
  }
}

customElements.define("my-app", ManualApp);
document.body.innerHTML = "<my-app></my-app>";

Actual results:

Calling any method inside constructor leads to TypeError. But if class not extended HTMLElement, I get expected result

class ManualApp {
  constructor() {
    this._log('hello world') // ok
  }

  _log(str) {
    console.log(str);
  }
}

Also, I'm getting expected result if I run this con in regular web page, not inside extension's content_script

Expected results:

When <my-app> created in document, I expect to see hello world in console without errors.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'WebExtensions::Untriaged' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.