redux array reducer code example

Example 1: redux reducer

const Reducer = (state=[],action) =>{
	switch(action.type){
      case'add':
        return [...state,action.payload]
      default:
        return state ;
    }
}

Example 2: js immutable update object

function updateVeryNestedField(state, action) {
  return {
    ...state,
    first: {
      ...state.first,
      second: {
        ...state.first.second,
        [action.someId]: {
          ...state.first.second[action.someId],
          fourth: action.someValue
        }
      }
    }
  }
}