undefined

<!DOCTYPE html>
<html>

<head>
  <link href="//cdn.jsdelivr.net/picnicss/4.1.1/picnic.min.css" rel="stylesheet">
  <link rel="stylesheet" href="style.css">
  <meta charset="utf-8">
  <title>Mag.JS</title>
</head>

<body>

  <nav>
    <h1>Hello Mag.JS!</h1>
    <a target="_tab" href="https://github.com/magnumjs/mag.js">GitHub</a>
  </nav>

  <article class="card">
    <header>
      <h2>Lists of Things!</h2>
    </header>

    <footer>

      <div id="app">
        <input>
        <button class="mainButton">Add List
        </button>
        <div>
          <ul class="lists">
            <li>
              <a></a>
            </li>
          </ul>
          <ol class="items">
            <li>
              <a></a>
            </li>
          </ol>
        </div>
      </div>

    </footer>
  </article>


  <script src="//rawgit.com/magnumjs/mag.js/master/mag-latest.min.js"></script>
  <script src="//rawgit.com/magnumjs/mag.js/master/dist/mag.addons.0.22.min.js"></script>

  <script src="todos.js"></script>
  <script src="app.js"></script>

</body>

</html>

var app = {}

app.controller = function(props) {
  this.selectedListId = null
  this.button = {
    _onClick: () => {
      if (this.input) {
        if (this.selectedListId === null) {
          props.todos.addList(this.input);
        } else {
          props.todos.addItemToList(this.selectedListId, this.input);
        }
        this.input = '';
      }
    }
  }
}

app.view = function(state, props) {

  state.lists = {
    li: props.todos.lists.map(function(list, id) {
      return {
        a: {
          _onClick: function() {
            if (state.selectedListId != id) {
              //toggle
              state.selectedListId = id;
              state.button._text = 'Add Item to ' + list.name
            } else {
              state.selectedListId = null
              state.button._text = 'Add List'
            }
          },
          _text: list.name
        }
      }
    })
  }

  state.items = {
    li: state.selectedListId !== null ? props.todos.getListById(state.selectedListId).items.map(function(item) {
      return {
        a: {
          _onClick: function() {
            alert(item.id)
          },
          _text: item.name
        }
      }
    }) : []
  }

}

var props = {
  todos: todos
}

mag.module("app", app, props)

li:empty, ol:empty, 
.hide {
  display: none;
}

a {
  display: block;
}

a:after {
  content: " \bb";
}

.mainButton {
  font-size: 1.5em;
}

nav a {
  float: right;
  margin-top: -50px;
}

body {
  background: #fff;
  text-align: left;
  width: 90%;
  max-width: 960px;
  margin: 0 auto;
  padding: 20px 0 0;
}

nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3em;
  padding: 0 .6em;
  background: #fff;
  box-shadow: 0 0 0.2em rgba(17, 17, 17, 0.2);
  z-index: 10000;
  transition: all .3s;
  transform-style: preserve-3d;
}

header {
  font-weight: bold;
  position: relative;
  border-bottom: 1px solid #eee;
  padding: .6em .8em;
}

footer {
  padding: .8em;
}

article {
  top: 100px;
}

.card {
  max-width: 100%;
  display: block;
  position: relative;
  box-shadow: 0;
  border-radius: .2em;
  border: 1px solid #ccc;
  overflow: hidden;
  text-align: left;
  background: #fff;
  margin-bottom: .6em;
  padding: 6px;
  transition: all .3s ease;
}

ul, ol {
  width:50%;
  float:left;
}

#Mag.JS

## plunk boilerplate of "Things"

Basic Mag.JS boilerplate to count and create a list of things dynamically.

Example of external state and updates

var todos = {
  lists: [],
  addList: function(listName) {
    return todos.lists.push({
      name: listName,
      items: []
    })
  },
  getListById: function(listId) {
    return todos.lists[listId];
  },
  addItemToList: function(listId, item) {
    var List = todos.getListById(listId);
    List.items.push({
      name: item
    });
  }
};