React

by nirus

HTML

<div id="app"></div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
}

li {
  margin: 8px 0;
}

h2 {
  font-weight: bold;
  margin-bottom: 15px;
}

.done {
  color: rgba(0, 0, 0, 0.3);
  text-decoration: line-through;
}

input {
  margin-right: 5px;
}

React

const initialState = {
  items: [
    { text: "Learn JavaScript", done: false },
    { text: "Learn React", done: false },
    { text: "Play around in JSFiddle", done: true },
    { text: "Build something awesome", done: true }
  ]
};

function appReducer(state, action) {
  switch (action.type) {
    case 'ITEM_STATUS_CHANGE':{
    	let affected = state.items.slice();
      affected[action.index].done = !affected[action.index].done;
      return Object.assign({}, state,  { items: affected });
    }
      
    case 'ADD_ITEM_TO_LIST':{
      let affected = state.items.slice();
      affected.push({ text: action.data, done : false})   
      return Object.assign({}, state,  { items: affected });
    }
    
    default:
      throw new Error();
  }
}

function TodoApp(props){
	const [state, dispatch] = React.useReducer(appReducer, initialState);
    
	return (
      <div>
        <h2>Todos: 
          <input type="text" id="todoTextItem"/>
          <button 
          onClick={()=>{
          		dispatch({
              	type: 'ADD_ITEM_TO_LIST',
                data: window.todoTextItem.value
              })
          }}
          >Add Item</button>
        </h2>
        <ol>
        {state.items.map((item, index) => (
          <li key={index}>
            <label>
              <input 
                type="checkbox"
                checked={item.done}
                onChange={()=>{
                	dispatch({
                    type: 'ITEM_STATUS_CHANGE',
                    index: index,
                  })
                }}
              /> 
              <span className={item.done ? "done" : ""}>{item.text}</span>
            </label>
          </li>
        ))}
        </ol>
      </div>
    );
}

ReactDOM.render(<TodoApp />, document.querySelector("#app"))