uniapp上传图片转base64码（PC端）

uni.chooseImage({
    count: 9,
    success: res => {
        this.imageList = this.imageList.concat(res.tempFilePaths);
        console.log(res);
        // this.tempFilePaths = res.tempFilePaths[0];
        this.urlTobase64(res.tempFilePaths[0]);
    }
});

//转base64码
urlTobase64(url) {
    uni.request({
        url: url,
        method: 'GET',
        responseType: 'arraybuffer',
        success: res => {
            let base64 = wx.arrayBufferToBase64(res.data); //把arraybuffer转成base64
            base64 = 'data:image/jpeg;base64,' + base64; //不加上这串字符，在页面无法显示
            console.log(base64);
        }
    });
},