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How can I get the value of var result in this code?

I know this is a basic problem but I'm looking for the solution since 3 days. Can you give me any suggestion please?

function foo(myCallback){
}

function bar() {
    var result = foo(function(){
        var result = "hello"; 
        return result;
    });
}

var showResult = bar();
alert(showResult);

How can I get the value of var result in this code?

I know this is a basic problem but I'm looking for the solution since 3 days. Can you give me any suggestion please?

function foo(myCallback){
}

function bar() {
    var result = foo(function(){
        var result = "hello"; 
        return result;
    });
}

var showResult = bar();
alert(showResult);

• javascript
• callback
• anonymous

Share Improve this question Follow edited Apr 4, 2016 at 11:23 Priya 1,35166 gold badges2121 silver badges4141 bronze badges asked Apr 4, 2016 at 10:58 zm455zm455 49911 gold badge1111 silver badges2626 bronze badges 2

• You can get it in the callback – Rayon Commented Apr 4, 2016 at 10:59
• function foo(myCallback) { } function bar(cb) { foo(function() { var result = "hello"; cb(result); }); } bar(function(res) { alert(res); }); – Rayon Commented Apr 4, 2016 at 11:02

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3 Answers 3

Sorted by: Reset to default 6

You need to call the callback and return the value of it and inside your bar function, you need to return the result as well

function foo(myCallback){
    // return the value of the call myCallback()
    return myCallback();
}

function bar(){
    var result = foo(function(){
        var result = "hello"; 
        return result;
    });
    // return the result
    return result;
}
var showResult = bar();
alert(showResult);

A bit simplified it could be

function foo(myCallback){
    return myCallback();
}

function bar(){
    return foo(function(){
        return "hello"; 
    });
}
var showResult = bar();
alert(showResult);

You are missing the return statements. It isn't clear what you want to return.

It works like this:

function foo(myCallback){
  return myCallback();
}

function bar(){
    var result = foo(function(){
        var result = "hello"; 
        return result;
    });
  return result;
}
var showResult = bar();
alert(showResult);

You are stuck using callbacks, but fortunately you can pass parameters in your callback functions:

// define your functions
function foo(myCallback){
    myCallback();
}

function bar(callback){
    var result = foo(function(){
        var result = "hello"; 
        callback(result);
    });
}

// now run it
bar(function(showResult){
    alert(showResult);
});

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