How to set a nested object value when the key is a variable name

set.nested.object.value.js

const action = {
  id: "last_name",
  value: "Carney"
};

const state = {
  inputs: {
    first_name: {
      value: "Joe"
    },
    last_name: {
      value: ""
    }
  }
};

const newState = Object.assign({}, state, {
  inputs: Object.assign({}, state.inputs, {
    [action.id]: Object.assign({}, state.inputs[action.id], {
      value: action.value
    })
  })
});

/*
console.log(newState)

{
  inputs: {
    first_name: {
      value: "Joe"
    },
    last_name: {
      value: "Carney"
    }
  }
}

*/

Don't know how to do it in one line, but can only think of this.

var newInputs = {...state.inputs}
newInputs[action.id] = action.value
const newState = {
  ...state,
  inputs: newInputs
}