Vue

HTML

<div id="app">
  <input type="text" @keyDown="toggle">
  <div v-for="key in keys">key: {{ key }}</div>
</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;
}

del {
  color: rgba(0, 0, 0, 0.3);
}

Vue

new Vue({
  el: "#app",
  data: { keys:[] },
  methods: {
  	toggle: function(event){      
      this.keys.push(event.key);
    }
  }
})