Node js ES6 classes with require

Question

So up until now  i have created classes and modules in node js the following way       var fs   require  fs     var animalModule    function                     Constructor initialize object         constructor             var Animal   function  name            this name   name              Animal prototype print   function              console log  Name is     this name               return           Animal  Animal              module exports   animalModule      Now with ES6  you are able to make  actual  classes just like this   class Animal    constructor name       this name   name        print        console log  Name is     this name          Now  first of all  i love this    but it raises a question  How do you use this combined with node js s module structure   Say you have a class where you wish to use a module for the sake of demonstration say you wish to use fs  so you create your file     Animal js  var fs   require  fs    class Animal    constructor name       this name   name        print        console log  Name is     this name          Would this be the right way    Also  how do you expose this class to other files within my node project  And would you still be able to extend this class if you re using it in a separate file   I hope some of you will be able to answer these questions

User · Answer

Using Classes in Node -

Here we are requiring the ReadWrite module and calling a makeObject(), which returns the object of the ReadWrite class. Which we are using to call the methods. index.js

const ReadWrite = require('./ReadWrite').makeObject();
const express = require('express');
const app = express();

class Start {
  constructor() {
    const server = app.listen(8081),
     host = server.address().address,
     port = server.address().port
    console.log("Example app listening at http://%s:%s", host, port);
    console.log('Running');

  }

  async route(req, res, next) {
    const result = await ReadWrite.readWrite();
    res.send(result);
  }
}

const obj1 = new Start();
app.get('/', obj1.route);
module.exports = Start;

ReadWrite.js

Here we making a makeObject method, which makes sure that a object is returned, only if a object is not available.

class ReadWrite {
    constructor() {
        console.log('Read Write'); 
        this.x;   
    }
    static makeObject() {        
        if (!this.x) {
            this.x = new ReadWrite();
        }
        return this.x;
    }
    read(){
    return "read"
    }

    write(){
        return "write"
    }


    async readWrite() {
        try {
            const obj = ReadWrite.makeObject();
            const result = await Promise.all([ obj.read(), obj.write()])
            console.log(result);
            check();
            return result
        }
        catch(err) {
            console.log(err);

        }
    }
}
module.exports = ReadWrite;

For more explanation go to https://medium.com/@nynptel/node-js-boiler-plate-code-using-singleton-classes-5b479e513f74

User · Answer

In class file you can either use   module exports   class ClassNameHere    print       console log  In print function           or you can use this syntax  class ClassNameHere   print      console log  In print function          module exports   ClassNameHere    On the other hand to use this class in any other file you need to do these steps  First require that file using this syntax  const anyVariableNameHere   require  filePathHere     Then create an object const classObject   new anyVariableNameHere     After this you can use classObject to access the actual class variables

User · Answer

Just treat the ES6 class name the same as you would have treated the constructor name in the ES5 way  They are one and the same    The ES6 syntax is just syntactic sugar and creates exactly the same underlying prototype  constructor function and objects    So  in your ES6 example with      animal js class Animal              var a   new Animal     module exports    Animal  Animal     You can just treat Animal like the constructor of your object  the same as you would have done in ES5    You can export the constructor   You can call the constructor with new Animal     Everything is the same for using it   Only the declaration syntax is different   There s even still an Animal prototype that has all your methods on it   The ES6 way really does create the same coding result  just with fancier nicer syntax     On the import side  this would then be used like this   const Animal   require    animal js   Animal   let a   new Animal        This scheme exports the Animal constructor as the  Animal property which allows you to export more than one thing from that module   If you don t need to export more than one thing  you can do this      animal js class Animal              module exports   Animal    And  then import it with   const Animal   require    animal js     let a   new Animal

User · Answer

Yes  your example would work fine   As for exposing your classes  you can export a class just like anything else   class Animal       module exports   Animal    Or the shorter   module exports   class Animal         Once imported into another module  then you can treat it as if it were defined in that file   var Animal   require    Animal     class Cat extends Animal

User · Answer

The ES6 way of require is import  You can export your class and import it somewhere else using import   ClassName   from  path to ClassName syntax   import fs from  fs   export default class Animal      constructor name       this name   name          print        console log  Name is     this name          import Animal from  path to Animal js

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