nodeJs回调共享变量？

Question

So i have a problem with my nodejs code. I try to use this function to collect some information from some servers.

Background: I have some server which are only control and monitoring stuff and some others which are for working. I call the functions in my code like this

// 1 callback    
cmd.execute('getInformationScript ' + controlToken, function(queryResult){
        exctractInfo(queryResult, function(result){
          setcNodes(result)
        });
    });

//2 callback
cmd.execute('getInformationScript ' + imageToken, function(queryResult){
        exctractInfo(queryResult, function(result){
          setiNodes(result)
        });
    });


function exctractInfo(jsonString, callbackSucc){
  var callbackArray = [];
  var callbackResultArray = []

  if(jsonString != null){
    imageNodeArray = JSON.parse(jsonString);

    for(imageNodes in imageNodeArray){

      for(imageDetail in imageNodeArray[imageNodes]){

        if ('name' in imageNodeArray[imageNodes][imageDetail]){
              var name = imageNodeArray[imageNodes][imageDetail]['name'];
              callbackArray.push(imageNodeArray[imageNodes][imageDetail])

              // variable problem
              cmd.execute('getInfomationFromServer.sh '+name+'', function(shellResult){
               callbackResultArray.push(JSON.parse(shellResult));
              if(callbackResultArray.length == callbackArray.length){
                   imageNodeArray[imageNodes] = mapCallbacks(callbackArray,callbackResultArray);

                   callbackSucc(imageNodeArray);
                   imageNodeArray = []
              }
          });
        }
      }
    }
  }
}

After some debugging i can see that my Arrays where i store my callbacks to count them seem to be overwritten. So now a really stupid question ... why? I allays tough every callback function has it own scope so why they overwriting each other.

I really hope you can help me this is driving me crazy.

Answer 1

You didn't declare imageNodeArray . In JavaScript, if you assign a value to an identifier without declaring that identifier via the var keyword, then the variable is implicitly created in the global scope.

You need:

var imageNodeArray = JSON.parse(jsonString);