Defining read-only properties in JavaScript

Question

Given an object obj, I would like to define a read-only property \'prop\' and set its value to val. Is this the proper way to do that?

Answer 1

You could instead use the writable property of the property descriptor, which prevents the need for a get accessor:

var obj = {};
Object.defineProperty(obj, "prop", {
    value: "test",
    writable: false
});

As mentioned in the comments, the writable option defaults to false so you can omit it in this case:

Object.defineProperty(obj, "prop", {
    value: "test"
});

This is ECMAScript 5 so won't work in older browsers.