Delete an object within an outer object not working

It sounds like NAME is a non-configurable property. That means you can't delete it I'm afraid, as deleting (removing) a property counts as "configuring" it (as does changing the configurable flag on the property).

You can see what the configuration of the property is by using Object.getOwnPropertyDescriptor. In your case it probably will either not show a configurable property at all (because false is the default) or more likely it'll show configurable: false.

Here's an example which shows using getOwnPropertyDescriptor and demonstrates the error you're getting:

"use strict";
const object = { };
Object.defineProperty(object, "NAME", {
    value: {hello: 3838383, goodbye: 3474737},
    configurable: false,
    writable: true
});
console.log(Object.getOwnPropertyDescriptor(object, "NAME"));
delete object.NAME;

If the property is writable, you can assign some other value to itm, such as null or undefined:

object.NAME = null;

But if it's also non-writable, you can't do that, either.

As a final resort, you could create a new object and only copy the properties to it that you want, and assign that new object to the variable or property you're using to refer to the object. For instance:

object = Object.fromEntries(
    Object.entries(object)
      .filter(([key]) => key !== "NAME")
);

Live Example:

"use strict";
let object = {
    NAME2: {hello: 3838383, goodbye: 3474737}
};
Object.defineProperty(object, "NAME", {
    value: {hello: 3838383, goodbye: 3474737},
    configurable: false, // Just here for emphasis, false is the default
    writable: false      // same
});
console.log(Object.getOwnPropertyDescriptor(object, "NAME"));

// Can't do this: delete object.NAME;
object = Object.fromEntries(
    Object.entries(object)
      .filter(([key]) => key !== "NAME")
);
console.log(object);

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