basicReduxFunctions.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Document</title>
  <script src="redux.js"></script>
  <style>
    body {
      font-family: Arial, Helvetica, sans-serif;
    }

    label {
      display: inline-block;
      width: 100px;
      padding: 5px;
    }

    #result {
      padding: 5px;
    }
  </style>
</head>

<body>
  <div>
    <label for="firstName">First Name:</label>
    <input type="text" name="firstName" id="firstName">
    <button onclick="handleFirstNameUpdate()">Update</button>
  </div>
  <div>
    <label for="lastName">Last Name:</label>
    <input type="text" name="lastName" id="lastName">
    <button onclick="handleLastNameUpdate()">Update</button>
  </div>
  <div>
    <label for="birthday">Birthday:</label>
    <input type="text" name="birthday" id="birthday">
    <button onclick="handleBirthdayUpdate()">Update</button>
  </div>
  <div id="result">

  </div>
  <script type="text/javascript">
  
    // An initial state is to be passed to the Reducer function
    const initState = {
      firstName: 'Conway',
      lastName: 'Liu',
      birthday: '10/1/1970'
    }

    // A Reducer function is a pure function that takes in the previous state, 
    // the action to be dispatched, and return a new state for the store to keep
    const myReducer = (state, action) => {
      if (!state) state = initState;

      switch (action.type) {
        case 'CHANGE_FIRST_NAME':
          return {
            ...state,
            firstName: action.data
          }
        case 'CHANGE_LAST_NAME':
          return {
            ...state,
            lastName: action.data
          }
        case 'CHANGE_BIRTHDAY':
          return {
            ...state,
            birthday: action.data
          }
        default:
          return state;
      }
    }

    const store = Redux.createStore(myReducer);
    console.log("Store State", store.getState())

    const handleFirstNameUpdate = () => {
      store.dispatch({
        type: 'CHANGE_FIRST_NAME', 
        data: document.getElementById('firstName').value
      })
    }

    const handleLastNameUpdate = () => {
      store.dispatch({
        type: 'CHANGE_LAST_NAME',
        data: document.getElementById('lastName').value
      })
    }

    const handleBirthdayUpdate = () => {
      store.dispatch({
        type: 'CHANGE_BIRTHDAY',
        data: document.getElementById('birthday').value
      })
    }
  
  </script>
  <script>
    {
      const { firstName, lastName, birthday } = store.getState();
      document.getElementById('result').innerText = `${firstName} ${lastName} was born on ${birthday}`

      // Subscript to the state change event so we can update the UI whenever the state is changed
      store.subscribe(() => {
        const { firstName, lastName, birthday } = store.getState();
        console.log(store.getState())

        document.getElementById('result').innerText = `${firstName} ${lastName} was born on ${birthday}`
      })
    }
  </script>
</body>

</html>