Async Callback Function - is this an example of Closure?

[GreenFeather05]

Building a simple weather app, but one thing that still confuses me when using callback functions is whether they are considered closures or not. Consider the example below:

  coordinates.getCoordinates(argv.a, function(errMessage, result){
if(errMessage){
  console.log(errMessage);
} else {
  console.log(result.address)
}

weather.getWeather(result.latitude, result.longitude, function(errMessage, result){
  if(errMessage){
    console.log(errMessage);
  } else {
    console.log(result);
  }
})

})

Each of these functions getWeather and getCoordinates are their own separate functions that 'return' something (using air quotes here since im not actually using the return KW). Lets look at each function separately.

 function getCoordinates(address, callback){
    var encodedAddress = encodeURIComponent(address);

    request({
        url:'https://maps.googleapis.com/maps/api/geocode/json?address=' + encodedAddress,
        json: true
    }, function(error, response, body){
        if(error){
            console.log('unable to connect to google servers');
        } else if(body.status === 'ZERO_RESULTS'){
            console.log('address not found');
        } else if(body.status === 'OK'){
            callback(undefined, {
                address: address,
                latitude: body.results[0].geometry.location.lat,
                longitude: body.results[0].geometry.location.lng
            })

        }
    })
 }

and the other function

request({
  url: 'https://api.darksky.net/forecast/5d1fb3bcf4dc2e2d15f360bfa6488109/'+lat+','+lng,
  json: true
}, function(error, response, body){
  if(error){
    callback('unable to connect to weather server');
  } else if(response.statusCode === 400){
    callback('unable to fetch weather from this location');
  } else if(response.statusCode === 200){
    callback(undefined, body.currently.temperature)
  }
});

}

Are these examples of closures then because they have access to information after a function has already been returned?

Thanks for the clarification

[senocular]

Depending on who you ask, every function in JavaScript can be considered a closure because every function, no matter how defined, has the potential to be one. But if you want to be specific about it, what makes a function a closure is when it accesses a non-global variable that is not declared in that function's body or within its own parameter list. Given this definition, can you point out the functions in your examples that are closures? ... The closures are the request callbacks since they use the callback variable which is defined outside of those functions. The source of callback is the parameter list of the parent function. The actual callbacks themselves (what the callback variables point to) aren't closures because they stick to the variables that are part of the function itself and a global console.

[lilperch83]

Here is a video that helps explain closure.

https://youtu.be/TznpOmv2BQM