javascript - Node: get function response synchronously

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65879680/node-get-function-response-synchronously

Answer 1

//Using callback

const tempIsEmailExistsInDb = isEmailExistsInDb("[email protected]", function(res) {
        if (res) {//do something
         }
      });
        
           const isEmailExistsInDb = (usrEmail, cb) => {
            let tempCount;
            userModel.countDocuments( {"email": usrEmail}, function (err, count){
                  tempCount = count;
                  cb((tempCount > 0))
              });
             
         };

Also for using async method

     router.get('/' , async (req, res) => {
        const isEmail = await isEmailExistsInDb("[email protected]");
        if (isEmail > 0) {

        }

     })

 const isEmailExistsInDb = async (usrEmail, cb) => {
                
                let tempCount = await userModel.countDocuments( {"email": usrEmail});

                return tempCount;
    
             };