// base64转文件
export const dataURLtoFile = (image, filename) => {
    var arr = image.split(",");
    var mime = arr[0].match(/:(.*?);/)[1];
    var bstr = atob(arr[1]);
    var n = bstr.length;
    var u8arr = new Uint8Array(n);
    while (n--) {
      u8arr[n] = bstr.charCodeAt(n);
    }
    let file = new File([u8arr], filename, { type: mime })
    return  file;
}

// 第一个参数为你想生成的固定的文字开头比如: 微信用户xxxxx
// 第二个为你想生成出固定开头文字外的随机长度
export const random = ( randomLength) =>{
  // 兼容更低版本的默认值写法
  // prefix === undefined ? prefix = "" : prefix;
  randomLength === undefined ? randomLength = 3 : randomLength;

  // 设置随机用户名
  // 用户名随机词典数组
  let nameArr = [
      ["中","笑","贝","凯","歌","易","仁","器","义","礼","智","信","友","上","都","好","无","九","钰","玉","忠","孝","卿","聪","澜","纯","毓","悦","昭","冰","爽","琬","茗","羽","希","宁"],
      ["秀","娟","英","华","慧","巧","美","娜","静","淑","惠","珠","翠","雅","芝","玉","萍","红","娥","玲","芬","芳","燕","彩","春","菊","轮","翰","朗","伯","言","若","鸣","朋","斌","梁","栋","维"]
  ]
  // 随机名字字符串
  // let name = prefix;
  let name = "";

  // 循环遍历从用户词典中随机抽出一个
  for (var i = 0; i < randomLength; i++) {
      // 随机生成index
      let index = Math.floor(Math.random() * 2);
      let zm = nameArr[index][Math.floor(Math.random() * nameArr[index].length)];
      // 如果随机出的是英文字母
      if (index === 1) {
          // 则百分之50的概率变为大写
          if (Math.floor(Math.random() * 2) === 1) {
              zm = zm.toUpperCase();
          }
      }
      // 拼接进名字变量中
      name += zm;
  }
  // 将随机生成的名字返回
  return name;
}