Question

Does anyone have any example implementation of making individual object props readOnly/non-configurable? I mean primitive data types. Have tried using ES5 Object API, but hitting a brick wall.

I can’t show code, because it’s still at that “messy” phase, but basically I’m iterating through an outside object which, itself, holds numeruos objects. Those objects each hold various primitive data types. I have made the outer objects readOnly, non-config, etc, but can’t figure out how to do likewise for individual props, the innermost props.

So, if outer.inner.prop === "Hello", I want to make that value readOnly.

Thanks!

UPDATE

I just figured this out, it was all in the for loop I was using to iterate over props. Now I’ve actually get data descriptors for the props, even the primitive ones. 🙂 Thanks all!

Answer 1

You have to iterate through the inner object, since there is no way to deep-freeze an object using standard ES5 methods.

function deepFreeze(obj) {
    Object.keys(obj).forEach(function (key) {
        if (typeof obj[key] == 'object')
            deepFreeze(obj[key]);
    });
    Object.freeze(obj);
}

Edit:
Also works for defineProperty if you don’t want to freeze:

function deepWriteProtect(obj) {
    Object.keys(obj).forEach(function (key) {
        if (typeof obj[key] == 'object')
            deepWriteProtect(obj[key]);
        Object.defineProperty(obj, key, { writable: false });
    });
}