Update object (Nested) with react-addons-update

index.js

import update from 'react-addons-update';

let nextState = update(this.state.cards, {
    [index] : {
        tasks: {$splice: [[taskIndex, 1]]}
    }
});


//-----------------------------------------------------

let nextState = update(this.state.cards, {
    [cardIndex] : {
        tasks: {
            [taskIndex]: {
                done: { //(Done value = true or false)
                    $apply: (done) => {
                        newDoneValue = !done;
                        return newDoneValue;
                    }
                }
            }
        }
    }
});


//-----------------------------------------------------

let newTask = {id: Date.now(), name: taskName, done: false };
let nextState = update(this.state.cards, {
    [cardIndex] : {
        tasks: {$push: [newTask]}
    }
});