Changing ImmutableJS nested object with List and return whole state (Redux)

Question

My state is a nested Immutable thing:

const state = Map({ counter: 0, 
                    people: List([
                        Map({name: "John", age: 12, etc...}),
                        Map({name: "Jim", age: 13, etc...}),
                        Map({name: "Jack", age: 21, etc...})
                     ])
                  });

So I have a Map, which holds a counter and List of Maps. I have simplified things here, but say I want to change some properties of John in my reducer.

Right now I'm doing something like this:

    var newState = state
                .get('people') //get the list
                .get(action.payload.pos) //pos is an integer, & describes the position of the object in the List
                .set('name', action.payload.name)
                .set('age', action.payload.age);

My problem is that I don't know how to set properties in John and get back the whole state , - so I can return it in my reducer. Right now what I am getting back is only the very part I am changing.

A second problem is this very long way to write all of this down. I know that there is a syntax for nested structures, but I have a List here, which kind of breaks this, so I am a bit stuck.

Answer 1

You can use .findIndex to find the index to update (if you don't already have it), and then use the index in a .updateIn call, together with .merge to merge the old and the new values.

 const state = new Immutable.Map({ counter: 0, people: new Immutable.List([ new Immutable.Map({name: "John", age: 12, otherVal: 'a'}), new Immutable.Map({name: "Jim", age: 13, otherVal: 'b'}), new Immutable.Map({name: "Jack", age: 21, otherVal: 'c'}) ]) }); const newValues = { name: 'Jones', age: 100}; // find index to update const indexToUpdate = state .get('people') .findIndex(person => person.get('name') == 'Jim'); // use .updateIn to perform a merge on the person of interest const newState = state.updateIn( ['people', indexToUpdate], person => person.merge(newValues) ); console.log( 'new state is:\\n', JSON.stringify(newState.toJS(), null, 2) ); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/3.7.2/immutable.min.js"></script>