object literals for redux reducers

after.js

// O(1)
const todo = (state, action) => {
  const actions = {
    ADD_TODO: () => {
      return {
        id: action.id,
        text: action.text,
        completed: false
      }
    },
    TOGGLE_TODO: () => {
      if (state.id !== action.id) return state
      return {
        ...state,
        completed: !state.completed
      }
    }
  }
  return {
    default: state,
    ...actions
  }[action.type || 'default']
}

before.js

// O(n)
const todo = (state, action) => {
  switch (action.type) {
    case 'ADD_TODO':
      return {
        id: action.id,
        text: action.text,
        completed: false
      }
    case 'TOGGLE_TODO':
      if (state.id !== action.id) {
        return state
      }
      return {
        ...state,
        completed: !state.completed
      }
    default:
      return state
  }
}

This is super helpful and readable. Thanks 😊