SOURCE

var app6 = new Vue({
    el: '#app',
    data: {
        value: 'Hello Vue!'
    },
    mounted(){
        this.loadImg()
    },
    methods:{
        loadImg(){
            var qr = window.qr = new QRious({
                element: document.getElementById('qrious'),
                size: 250,
                value: this.value
            });
            return qr.toDataURL()
        }
    }
})

<div id="app">
    <img :src="loadImg()">
  <input v-model="value">
</div>