Can't pass parent function argument to child anonymous function

Question

In one of the background files of my chrome extension I'm checking for cookies and ran into a problem. In my function chrome.cookies.get({"url": domain, "name": name},function(cookie) {}); I am able to get the cookie object and pass it into the last parameter (an anonymous function) as the variable cookie and access it's value with cookie.value .

The problem is that I am only able to send a return response from the parent function and not the nested anonymous function from within the chrome.cookies.get call.

In my example below I am able to return a response (verified with an alert on another page) with value1 but value2 is never being returned... After doing a lot of reading I think I narrowed down the problem to a scoping error... By that I mean my response call sendResponse (a parameter in the parent function) is not being accessed by the nested anonymous function.

function getCookies(request, sender, sendResponse, domain, name) {
    chrome.cookies.get({"url": domain, "name": name}, function(cookie) {
            sendResponse({"myvar":"value2"}); //DOES NOT WORK
            if(cookie){
                anotherFunction(cookie.value);
            }else{
                anotherFunction("0");
            }
    });
    sendResponse({"myvar":"value1"});  // WORKS
}

So basically, I just need to figure out some method to push my sendResponse parameter down to the anonymous function; or re-create a similar method that would not cause this scoping issue. Any assistance or guidance with this issue would be greatly appreciated. Thank you in advance for your time.

Answer 1

In reference to this issue Two way communication is returning error in Chrome Extension , did you returned true at the end of your onMessage listener? Worked in my case.

chrome.extension.onMessage.addListener(function(request, sender, sendResponse) { 
  // your getCookies call
  return true;
});

Answer 2

Hmm. How about forcing sendResponse into the cookie?

function getCookies(request, sender, sendResponse, domain, name) {
  Object.prototype.sendResponse=sendResponse;

  chrome.cookies.get({"url": domain, "name": name}, function(cookie) {
    cookie.sendResponse({"myvar":"value2"});
    if(cookie){
      anotherFunction(cookie.value);
    }else{
      anotherFunction("0");
    }
  });
}

Answer 3

Having completely not tested it, is there any reason you can't pass in a named callback instead?:

function getCookies(request, sender, sendResponse, domain, name) {
  var cb = function(cookie) {
    sendResponse({"myvar":"value2"});
    if(cookie){
      anotherFunction(cookie.value);
    }else{
      anotherFunction("0");
    }
  };
  chrome.cookies.get({"url": domain, "name": name}, cb);
  sendResponse({"myvar":"value1"});  // WORKS
}

sendResponse should still be in scope when cb gets called, no?

Answer 4

(I was just about to ask about it too, but I found your question)

just do this:

chrome.cookies.get({"url":"https://...","name":"..."}, function(cookie){
    chrome.tabs.sendMessage(sender.tab.id, {"cookie": cookie.value});
  });

ps next time try adding google-chrome-extension tag to your questions.