Spying on property?

[natanavra]

Is it possible to spy on properties without ES6 getters/setters?
e.g.:

let obj = {settings: {key: 'value'};
sinon.spy(obj);
sinon.assertTrue(obj.settings.key.called);

[Alexsey]

getters/setters are ES5 and yes, you have an option - use Proxy from ES6. But Sinon can help you here only by providing a spy that you can put in the getter to assert it later. Because spys, stubs and mocks are only for functions. That is because unit testing don't imply that you should ever spy on properties

[natanavra]

OK, thanks.
I was looking for a way to check if certain properties are being "used" by a function, something like a "litmus check"

[mroderick]

It IS possible to spy on getters/setters ... unfortunately, it hasn't been documented yet.

See #1606 for a solution