Referring to a callback

file1.js

// This file generates output
module.exports = function(callback) {
	callback('This is a model answer provided by Andrew Mead.');
};

file1B.js

var strOutput = require('./file1B.js');

strOutput(function(externalInput){
	console.log('External Input: ' + externalInput);
});

weather.js

module.exports = function(callback){
	/*
	(1) We need to use the request module
	(2) We need to also use the url with the api and necessary query parameters
	*/
	var request = require('request');
	var url = 'http://api.openweathermap.org/data/2.5/weather?q=Sutton,uk&appid=a0405ca935c126bca3f178e0230f75b5&units=metric';
	
	console.log('Got weather!');

	request({
		url: url,
		json: true
	}, function(error, response, body){
		if(error){
			callback('Unable to fetch the weather data!') ; 
			
		} else {
			
			console.log(JSON.stringify(body, null, 4));
			// Print out the name of the city and it's temperature
			callback ('In city: ' + body.name + ', ' + body.sys.country + ' the temperature is: ' +  body.main.temp + ' deg C.');
		}
		//The data is contained in the body argument
		//4 - is the number of spaces the data has to be indented by
	});
}

Thanks Andrew. I understand the explanation, but how do I make sense of that in future. If I see 'require ('request') ', I should simply think the request library is accessing the callback function. That is a bit hazy, but is a definite improvement on where I was with this. Many thanks.

Correct. If you're using a function someone else wrote, you're not going to see "callback" in your code.