gistfile1.js

class Base {
  constructor() {
    const privateVariable
    this._protectedVariable
    this.publicVariable
    function privateFunction() {}
  }
  
  _protectedFunction() {}

  publicFunction() {}
}

class Derived extends Base {
  constructor() {
    super()
  }
  
  _protectedFunction() {
    super._protectedFunction()
  }

  publicFunction() {
    super.publicFunction()
  }
}