功能：将base64图片字符串转换为 File 对象
参数说明：
dataurl base64图片字符串
filename：自定义文件名称

export const base64ToFile = (dataurl, filename="test") => {
    let arr = dataurl.split(','), mine = arr[0].match(/:(.*?);/)[1], bstr =atob(arr[1]), n = bstr.length, u8arr =new Uint8Array(n), suffix = mine.split("/")[1];
    while(n--){
        u8arr[n] = bstr.charCodeAt(n);
    }
    let theBlob = new Blob([u8arr], {type: mine})
    theBlob.lastModifiedDate = new Date()
    theBlob.name = `${filename}.jpg`
    console.log(theBlob)
    return theBlob
}