【JavaScript】プロトタイプ上のプロパティをインスタンスで上書き（オーバーライド）させない方法

const CF = function(){}
Object.defineProperty( 
  CF.prototype , "func" ,{
    writable:false , // デフォルト値のため省略可能
    value:function(){ console.log("func1") }
  });

const obj = new CF;
obj.func = 200; // TypeError

const obj = new CF;

Object.defineProperty( 
  obj , "func" ,{
    writable:true ,
    value:100
  });
obj.func = 200;
console.log( obj.func ); // 200

const CF = function(){
  this.prop1 = 100;
  return Object.seal( this );
}
CF.prototype.func = function(){ console.log("func1") };

const obj = new CF;
obj.func = 100; // TypeError

const class1 = class {
  constructor(){
    this.prop1 = 100;
    return Object.seal( this );
  }
  func(){ console.log("func1") }
};

const obj = new class1;

obj.func = 100;

const CF = function(){
  const nameList = ["func"];

  return new Proxy( this , {
    set:function ( target, property , value , receiver ){
        if( nameList.indexOf(property) >= 0 ) 
            throw new TypeError( `"${property}"は上書きできません` );
        return Reflect.set( ...arguments );
    }
  });
}


const obj = new CF;

obj.func = 200; // TypeError: "func"は上書きできません