vue环境中生成二维码

代码如下：

引入qrcode--------npm install qrcode
<template>
    <div>
        <div id='code'></div>
        <canvas id="canvas"></canvas>
    </div>
</template>
<script>
    import Vue from 'vue'
    import QRCode from 'qrcode'
    Vue.use(QRCode)
    export default {
        data() {
            return {
                codes: ''
            }
        },
        methods: {
            useqrcode() {
                var canvas = document.getElementById('canvas')

                QRCode.toCanvas(canvas, 'http://www.baidu.com', function(error) {
                    if (error) console.error(error)
                    console.log('success!');
                })
            }
        },
        mounted() {
            this.useqrcode();
        }
    }
</script>
<style>
    #canvas {
        width: 200px !important;
        height: 200px !important;
    }
</style>