How to change writable enumerable and configurable values of a Javascript object property?

Question

From the node repl:

foo = { bar: 'baz'};
console.log (Object.getOwnPropertyDescriptor(foo, 'bar'))

Returned value:

{ value: 'baz',
  writable: true,
  enumerable: true,
  configurable: true }

How do you change the writable enumerable, and configurable to false? What are these values called? Are they part of ES5.1? Are there more that the repl didn't output?

Answer 1

"How do you change the writable enumerable, and configurable to false?"

Object.defineProperty(foo, 'baz', {
    enumerable:false,
    writable:false,
    configurable:false
});

There's also Object.defineProperties, which is the same, except you can set multiple properties, and Object.create, which let's you create a new object, and set its prototype object, and its descriptors.

"What are these values called?"

They're property descriptors.

"Are they part of ES5.1?"

Yes, ES5.

"Are there more that the repl didn't output?"

More what, property descriptors? No.

Answer 2

squint:I think there is like a little typing error in your answer.

Your code:

Object.defineProperty(foo, 'baz', {
enumerable:false,
writable:false,
configurable:false
});

but the second argument must be the name of the property and not the value, so the correct code is:

Object.defineProperty(foo, 'bar', {
enumerable:false,
writable:false,
configurable:false
});