vue learning: setting styles with css classes

by giordanna

HTML

<script src="https://npmcdn.com/vue/dist/vue.js"></script>

<div id="app">
  <div class="demo" @click="attachRed = !attachRed" :class="divClasses"></div>
  <div class="demo" :class="{red: attachRed}"></div>
  <div class="demo" :class="[color, {red: attachRed}]"></div>
  <hr>
  <input type="text" v-model="color">
</div>

CSS

.demo {
  width: 100px;
  height: 100px;
  background-color: gray;
  display: inline-block;
  margin: 10px;
}

.red {
  background-color: red;
}

.green {
  background-color: green;
}

.blue {
  background-color: blue;
}

JavaScript

new Vue({
  el: '#app',
  data: {
    attachRed: false,
    color: 'green'
  },
  computed: {
    divClasses: function() {
      return {
        red: this.attachRed,
        blue: !this.attachRed
      }
    }
  }
});