findIndex problem with Immer and Redux Starter Kit - reactjs

Question

I have a redux state that I need to update, it looks like this:
[
{
date: moment("2019-06-15").toObject(),
attendance: [
{
name: "Ruben Hensen",
membershipNumber: "2084700",
attending: true,
present: false
},
{
name: "Peter Petersen",
membershipNumber: "2084701",
attending: true,
present: false
},
{
name: "Karel Kootjes",
membershipNumber: "2084702",
attending: true,
present: false
},
{
name: "Niedaar Mennekes",
membershipNumber: "2084703",
attending: true,
present: false
},
]
},
...
...
...
]
My reducer tries to find the correct week so it can update it later but is unable to find the correct week inside the array.
TOGGLE_PRESENCE: (state, action) => {
console.log(state);
console.log(action);
const index = state.findIndex(week => week.date === action.payload.date);
console.log(index);
}
The problem is that I use Redux Starter Kit and it uses Immer inside reducers. If I run my reducer this is the result of the console logs.
It's not able to find the correct week.
Any tips or pointers would be appreciated. I don't really understand Immer or the Proxy objects it uses.
Edit:
#markerikson solved the problem. I changed this:
const index = state.findIndex(week => week.date === action.payload.date);
to this:
const index = state.findIndex(week =>moment(week.date).isSame(action.payload.date));
And now it finds the correct index.

Answer 1

The moment instances are not going to be === equal to each other. You probably need to use Moment's APIs for comparing them, like:
const index = state.findIndex(week => week.date.isSame(action.payload.date));
Note that this part doesn't have anything to do with Immer or Redux Starter Kit specifically - it's that different object instances are going to have different references.