module.exports and exports NodeJS examples

module.js

//***************************
//sayhello.js
var sayhello1 = function() {  };
var sayhello2 = function() {  };
exports.sayhello1 = sayhello1;
exports.sayhello2 = sayhello2;

//index.js
var x = require('./sayhello.js');
x.sayhello1();

//***************************
//sayhello.js
function sayhello3() {  };
function sayhello4() {  };
exports.sayhello3 = myFunc3;
exports.sayhello4 = myFunc4;

//index.js
var y = require('./sayhello.js');
y.sayhello3();

//***************************
//sayhello.js
module.exports = exports = function() {
    console.log("Hello!");
};

//index.js
var sayHello = require('./sayhello.js');
sayHello(); // "Hello World!"

//***************************
//sayhello.js
exports.run = function() {
    console.log("Hello guys!");
}

//index.js
var sayHello = require('./sayhello');
sayHello.run(); // "Hello World!"

//***************************
//sayhello.js
module.exports = {
  sayHelloInEnglish: function() {
    return "Hello";
  },
       
  sayHelloInSpanish: function() {
    return "Hola";
  }
};

//index.js
var sayHello = require('./sayhello');
sayHello.sayHelloInEnglish();

//***************************
//sayhello.js
module.exports = {
  Hello: 'Hi!'
}

//index.js
var sayHello = require('./sayhello');
sayHello.Hello;

//***************************
//sayhello.js
var sayHello = {
    'sayHello1':'Hi!',
    'sayHello2':'Hello'
}
function sayHi(){
    console.log('Hi!!');
    return 'Hello'
}
exports.sayHello = requires;
exports.sayHi = sayHi;

//index.js
var x = require("./sayhello").sayHello.sayHello1;
var y = require("./sayhello").sayHi;
console.log(x)    //Hi!
console.log(y)    //function sayHi(){
                  //console.log('Hi!!');
                  //return 'Hello'
                  //}
console.log(y())  //Hi!! 
                  //Hello

//***************************
//require.js
var x = 5,
    z = 10;
exports.w = function(){
  return x + z //Function exported, takes variables x and z, makes sum and export perfectly the result.
}

//index.js
var y = require('./require');
console.log('y: '+y.w());

//***************************
//person.js
var name = 'yyy';
var age = 25;
var sex = 'F'; //Private, not exported.
function speak(name, age, sex){
    return 'My name is: '+name+' I am '+age+' years old and my sex is '+ sex; //It doesn't print sex var from external module.
}
function smile(){
    var smile_1 = 'I like smile!'
    return smile_1+' Ja';
}
function sing(){
    return 'La la la';
}
speak(name,age,sex); //Called function inner module is not executed in exported module.
console.log('Log function from module: ' + speak(name,age,sex));    //console.log is regardless printed if the function is or not exported.
console.log('Log variable from module: ' + name);                   //console.log is regardless printed if the function is or not exported.
module.exports = {
    name:name,
    age:age,
    //sex:sex, //sex is not exported.
    speak:speak,
    smile:smile,
    sing:sing
}

//index.js
var person = require('./person');
console.log('Log from index: ' + person.speak(person.name,person.age,person.sex) + '\n'); // sex is not exported from module thus is not printed.
console.log('Log from index: ' + person.smile());
console.log('Log from index: ' + person.sing());

//***************************

//errorHandle.js
module.exports = function (err, req, res, next) {
  const error = {};
  error.msg = err.msg || err.message || 'Unknown reason';
  const status = err.status || '400';
  return res.status(status).send(error);
}

//index.js
const errorHandle 	= require('./errorHandle');
console.log(errorHandle);