前段时间看了微信小程序的借书系统，看到了这种处理方法。嗯，想着以后也可以在项目中这样实施了。?️一个统一的处理方法，同时针对具体的请求还可以自定义一个异常的处理情况。

let $request = function() {
      return new Promise((resolve, reject) => {
        let num = Math.random() * 10;
        if (num >= 5) {
          resolve("simulate normal datas");
        } else {
          reject("simulate  unexpect error");
        }
      });
    };

    function $_http(a, b, c) {
      return $request().catch(res => {
        // 这里做统一处理的报错
        console.warn("wo can do sth here such as  throw modal alert error");
        return Promise.reject("this is the common  error ");
      });
    }

    $_http()
      .then(data => {
        console.log("this is correct steps ");
      })
      // 这里可以进一步追加各自异常情况的处理
      .catch(error => {
        console.warn("it is my individual handel error ", error);
        //  handel error codes
      })
      .finally(() => {
        console.log(
          "no matter what status it is  you can do sth here  eg: tips "
        );
      });