javascript - 异步函数不返回 json 对象

Question

public async validateToken(req, res): Promise<any> {

    const token = req.headers.authorization.split(" ")[1] || req.params.token;
    await this.redisClient.SISMEMBER("tokenBlackListSet", token, function(
        err,
        data
      ) {
        if (data) { // here i get data=1 as token is present in tokenBlackListSet
          return {  // so this  should be returned as json
            status: 400,
            error: "Invalid Token"
          };
        }
      });

}



// in other async function

const response = await validateToken(req,res);

console.log(response) // returned value is always undefined

Answer 1

由于 SISMEMBER 方法返回一个 bool 值，而不是回调返回的值，您可以返回一个您在回调中解析的新 Promise :

public async validateToken(req, res): Promise<any> {

  const token = req.headers.authorization.split(" ")[1] || req.params.token;

  return new Promise(function (resolve, reject) { // Here I create a new Promise that will resolve (or reject) when your callback is called
    this.redisClient.SISMEMBER("tokenBlackListSet", token, function(
      err,
      data
    ) {
      if (err) { // If there is an error, we reject the promise
        reject(err);
      }
      else if (data) { // If you have some data, the promise will resolve with the object
        resolve({
          status: 400,
          error: "Invalid Token"
        });
      }
    });

  }

}

请注意，我删除了 await，因为我们已经返回了一个 promise，所以它现在是多余的。