read the MDN documentation and found no corresponding instructions, but when I actually tested it, I found that _ under the getter, setter of class is not just a naming convention, but there are really special rules. For example:

class Test{
  constructor(){
  this.a = 1;
  }
  get a(){
  return this._a;
  }
  set a(value){
  this._a = value;
  }
  
}

const t = new Test();
**console.log("t.a", t.a); //1**

class Test2{
  constructor(){
  this.a = 1;
  }
  get b(){
  return this._a;
  }
  set b(value){
  this._a = value;
  }
  
}

const t2 = new Test2();
**console.log("t2.b", t2.b); //undefined**

getter named a can get the value of this.a through this._a . If getter is changed to return this.a; , it will loop infinitely. So it is necessary to use return this._a; , but there is no description in the document that class getter must use _.

getter named b cannot get this._a

excuse me, where can I write such a rule? Why is there such a design?