Faça JavaScript somente leitura da propriedade

Object.prototype.makeReadonly = function(property)
{
	var propValue = this['property'];
  	Object.defineProperty(this, property, {
    	value: propValue,
      	writable: false,
    });
};

var obj = {
	testStr: "Hello World!",
};

obj.makeReadonly('testStr');

obj.testStr = "hello world";
console.log(obj.testStr); // outputs "Hello World!"
Tilted Turtle