javascriptnode.jstry-catchtry-catch-finally

finally block running before try block ends db call


I am performing input operation on db and trying to return response.

    var response = {}
    try {
        db.put({},(err, data) => {
            if(err) {
                response["message"] = err.message
                response["code"] = 400
            } else {
                response["message"] = "Group created"
                response["code"] = 201
                response["body"] = data.Item   
            }
        })
    } catch (error) {
        response['message'] = "Something went wrong"
        response['code'] = 500
    } finally {
        return response
    }

This code returns null object on success whereas when I tried setting timeout after the db call it returned full response. I think finally block runs without awaiting db call response.


Solution

  • Yes, that would make sense if db.put is asynchronous.

    For DynamoDB it looks like you can return a Promise. You could then use await to wait for the response in order to return it.

    It would become something like this:

    const func = async() => {
      const response = {}
      try {
        try {
          const rv = await db.put({}).promise();
          response["message"] = "Group created"
          response["code"] = 201;
          response["body"] = rv.data.Item;
        } catch (err) {
          response["message"] = err.message;
          response["code"] = 400;
        }
      } catch (error) {
        response['message'] = "Something went wrong";
        response['code'] = 500;
      } finally {
        return response;
      }
    }
    func().then((val) => console.log(val));