Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

+ add another resource


Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource


Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.


Auto Save

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.


                //- DOM element where we will bootstrap VueJS

    | Todo List - VueJS 
    //- show number of remaining todo items - if any
      | ({{ itemsTodo.length }} pending)
  //- 1) run addTodo method on enter key
  //- 2) bind field value to 'newTodo' data property
    placeholder="Type and press enter..."
    //- 1) one 'li' element per item in 'todos' data array
    //- 2) conditionally add 'todos__completed' class if todo item is completed
    //- 3) toggle completion status on click
    //- 4) add transition attribute
      v-for="(todo,index) in todos",
      :class="{ 'todos__completed': todo.completed }",
      @click="todo.completed = !todo.completed",
      //- 1) run 'removeTodo' method on click
        | &times; 
      | {{ todo.text }}

  //- placeholder text if todos data array is empty
    | Nothing to do... yet!

  //- 1) delete all completed items on click
  //- 2) only show if remaining todo items
  ) Clear completed tasks


                /* ##### 🌍 Global Stuff 🌍 ##### */

@import url(',700')
$tint = #0099aa

  padding 1rem 1.5rem
  background darken(white, 3)
  font-family 'Open Sans', sans-serif
  @media(min-width 500px)
    padding-top 3rem
/* ##### 🔥 BEM + Stylus 🔥 ##### */

// the prefix
    margin-bottom 1rem
    padding .5rem .75rem
    border solid 2px darken(white, 15)
    width 15rem
    margin .5rem 0 1rem
      outline none
    margin 1rem 0
    padding 0
    position relative
    list-style none
    padding .5rem
    margin 0 .3rem .3rem 0
    background white
    display inline-block
    color darken(white, 40)

      cursor pointer
      color #666
    margin-right .5rem
    background tomato
    border none
    color white
    border-radius 50%
    height 1rem
    width 1rem
    display inline-block
    line-height 1
    font-size .8rem
    text-align center
    padding 0
      background darken(tomato, 15)

    background lighten($tint, 65)
    text-decoration line-through
    color $tint

      color darken($tint, 5)
    font-size 0.8rem
    color $tint
    font-size 0.9rem
    color #666
/* ##### transitions ##### */
    transition all .2s
    opacity 0
    display none


                const vm = new Vue({
  // The DOM element to bootstrap our Vue
  el: '#app',
  // Kick off with some initial state
  data: {
    newTodo: '',
    todos: [
      {text: 'drink coffee', completed: true},
      {text: 'eat breakkie', completed: false},
      {text: 'check e-mails', completed: false},
      {text: 'hang in slack', completed: false},
      {text: 'do some work', completed: false},
      {text: 'check twitter', completed: false},
      {text: 'seriously dude, work!', completed: false},
      {text: 'drink coffee', completed: false},
      {text: 'play in CodePen', completed: false}
  // keeping track of done / todo items
  computed: {
    itemsDone() {
      return this.todos.filter(todo => todo.completed)
    itemsTodo() {
      return this.todos.filter(todo => !todo.completed)
  // Let's implement our functionality in methods
  methods: {
    addTodo() {
      // create new todo object
      const newEntry = {
        text: this.newTodo,
        completed: false
      // if input field not empty...
      if (this.newTodo.length) {
        // ...push to todos array 
        // ...reset input field
        this.newTodo = '' 
    removeTodo(index) {
      // remove todo item
      this.todos.splice(index, 1)
    clearCompleted() {
      // only keep todo items not completed (see computed data)
      this.todos = this.itemsTodo