This document discusses using JavaScript at the backend with Node.js. It covers installing Node.js, creating a "Hello World" program, using Node's internal file system module, working with the Node Package Manager (NPM) to install external modules, and using an external module called lodash in a program.

1. JavaScript at Backend

2. Agenda

3. Agenda
1. What?

4. Agenda
1. What?
2.Installing

5. Agenda
1. What?
2.Installing
3.Hello World.

6. Agenda
1. What?
2.Installing
3.Hello World.
4.NodeJS Internal Modules

7. Agenda
1. What?
2.Installing
3.Hello World.
4.NodeJS Internal Modules
○fs(file-system) (sync vs async)

8. Agenda
1. What?
2.Installing
3.Hello World.
4.NodeJS Internal Modules
○fs(file-system) (sync vs async)
5. NPM

9. Agenda
1. What?
2.Installing
3.Hello World.
4.NodeJS Internal Modules
○fs(file-system) (sync vs async)
5. NPM
6. Using External Modules

10. What?

11. Installing
https://github.com/creationix/nvm

12. Hello World

13. You can checkout Demo form:
https://github.com/AmitThakkar/JavaScript-at-Backend-NodeJS

14. Node Internal Modules: fs
var fs = require('fs');
fs.unlinkSync('test2');
console.log('successfully deleted test2');

15. Node Internal Modules: fs
var fs = require('fs');
fs.unlinkSync('test2');
console.log('successfully deleted test2');

16. Node Internal Modules: fs
var fs = require('fs');
fs.unlinkSync('test2');
console.log('successfully deleted test2');

17. Node Internal Modules: fs
var fs = require('fs');
fs.unlink('test', function (err) {
if (err) throw err;
console.log('successfully deleted test');
});

18. Node Internal Modules: fs
var fs = require('fs');
fs.unlink('test', function (err) {
if (err) throw err;
console.log('successfully deleted test');
});

19. Node Internal Modules: fs
var fs = require('fs');
fs.unlink('test', function (err) {
if (err) throw err;
console.log('successfully deleted test');
});

20. You can checkout Demo form: https://github.com/AmitThakkar/JavaScript-at-
Backend-NodeJS

21. NPM
1. Node Package Manager
2. The NPM command-line tool is bundled with node.
3. npm init
4. npm install --save lodash
5. npm uninstall --save lodash

22. npm init

23. npm install --save lodash

24. npm uninstall --save lodash

25. You can checkout Demo form: https://github.com/AmitThakkar/JavaScript-at-
Backend-NodeJS

26. Using External Modules
var _ = require("lodash");
console.log(_.chunk(['a', 'b', 'c', 'd'], 2)); // [ [ 'a', 'b' ], [ 'c', 'd' ] ]
console.log(_.chunk(['a', 'b', 'c', 'd'], 3)); // [ [ 'a', 'b', 'c' ], [ 'd' ] ]
console.log(_.filter([4, 5, 6], function (n) {
return n % 2 == 0;
})); // [ 4, 6 ]

27. You can checkout Demo form: https://github.com/AmitThakkar/JavaScript-at-
Backend-NodeJS

28. Questions??

29. References:
Create Basic HTTP Server with Node.js