redux

redux.js

const INCREMENT = "INCREMENT"; // define a constant for increment action types
const DECREMENT = "DECREMENT"; // define a constant for decrement action types

// define the counter reducer which will increment or decrement the state based on the action it receives
const counterReducer = (state = 0, action) => {
  switch (action.type) {
    case INCREMENT:
      return state + 1;

    case DECREMENT:
      return state - 1;

    default:
      return state;
  }
};

// define an action creator for incrementing
const incAction = () => {
  return {
    type: INCREMENT
  };
};

// define an action creator for decrementing
const decAction = () => {
  return {
    type: DECREMENT
  };
};

// define the Redux store here, passing in your reducers
const store = Redux.createStore(counterReducer);

redux2.js

const ADD_TO_DO = "ADD_TO_DO";

// A list of strings representing tasks to do:
const todos = [
  "Go to the store",
  "Clean the house",
  "Cook dinner",
  "Learn to code"
];

const immutableReducer = (state = todos, action) => {
  switch (action.type) {
    case ADD_TO_DO:
      // don't mutate state here or the tests will fail

      return state.concat(action.todo);
    // or return [...state, action.todo]

    default:
      return state;
  }
};

// an example todo argument would be 'Learn React',
const addToDo = todo => {
  return {
    type: ADD_TO_DO,
    todo
  };
};

const store = Redux.createStore(immutableReducer);

redux3.js

const immutableReducer = (state = ["Do not mutate state!"], action) => {
  switch (action.type) {
    case "ADD_TO_DO":
      // don't mutate state here or the tests will fail
      let arr = [...state, action.todo];
      return arr;
    default:
      return state;
  }
};

const addToDo = todo => {
  return {
    type: "ADD_TO_DO",
    todo
  };
};

const store = Redux.createStore(immutableReducer);

redux4.js

const immutableReducer = (state = [0, 1, 2, 3, 4, 5], action) => {
  switch (action.type) {
    case "REMOVE_ITEM":
      // don't mutate state here or the tests will fail
      return [
        ...state.slice(0, action.index),
        ...state.slice(action.index + 1, state.length)
      ];
    // or return state.slice(0, action.index).concat(state.slice(action.index + 1, state.length));
    default:
      return state;
  }
};

const removeItem = index => {
  return {
    type: "REMOVE_ITEM",
    index
  };
};

const store = Redux.createStore(immutableReducer);

redux5.js

const defaultState = {
  user: "CamperBot",
  status: "offline",
  friends: "732,982",
  community: "freeCodeCamp"
};

const immutableReducer = (state = defaultState, action) => {
  switch (action.type) {
    case "ONLINE":
      // to enforce state immutability, return a new state object using Object.assign() method
      return Object.assign({}, state, { status: "online" });
    default:
      return state;
  }
};

const wakeUp = () => {
  return {
    type: "ONLINE"
  };
};

const store = Redux.createStore(immutableReducer);