Updating the array object in React state using immutability helper

Question

I am updating an object within an array in React state using immutability helper.

The object I want to modify is nested:

Answer 1

One way to do it would be using $set

let index = 0;
let newState = update(this.state, {
   a: {
     b: {
      [index]: {
               c: { $set: "new value"}
       }
    }
  }
});
this.setState(newState);

jsfiddle