opteamix

Node Js Training

Banuprakash C

Full Stack Architect,

Co-founder Lucida Technologies Pvt Ltd.,

Corporate Trainer,

Email: banu@lucidatechnologies.com; banuprakashc@yahoo.co.in

https://www.linkedin.com/in/banu-prakash-50416019/

https://github.com/BanuPrakash/opteamix

---

Softwares Required:

1. Node.js Latest LTS

2. Visual Studio Code

3. Docker Desktop

4. MySQL database [Docker]

==============================================

NodeJS by default uses commonJS module system

lib.js

module.exports.add = function(x,y) {

}

module.exports.sub = function(x,y) {

}

multiply = function(x,y) { }

other.js

const lib = require('./lib');

lib.add(4,5);

15 min Tea Break

Node Js project

fs, http, https, crypto, path ==> built-in module

NPM ==> Node Package Manager ==> to manage dependencies ==> like [Maven ==> pom.xml] ==> package.json configure dependencies which will be downloaded by NPM ==> can use to publish the package

https://www.npmjs.com/

==================== 1) simpleproject> npm init -y

creates package.json

ab -c 1000 -n 10000 http://localhost:3000/hextorgb?hex=ff00ff

=========================================================================

Day 2

=====

Nodejs ==> V8 ==> libuv ==> thread pool + Os Async helpers

Event loop

Nodejs built-in modules ==> fs, http, url, crypto, repl, ....

---

Nodejs project contains package.json ==> dependencies + development dependencies are configured [ Maven pom.xml]

NPM ==> Node Package Manager ==> manage dependecies

1. Initialize a Node.js Project create a folder npm init -y

===

Node.js by default uses CommonJS module system other module systems available [ AMD + ES6 + System]

============================= Testing ==> AAA ==> Assemble Action Assert

Unit Testing Frameworks for JavaScript:

1. Jasmine
2. Mocha
3. Jest

Mocha is a unit testing library but without any assertion libraries

Chai is an assertion library https://www.chaijs.com/

Install development dependecies:

npm i -D mocha chai request

OR

npm i --save-dev mocha chai request

"devDependencies": { "chai": "^4.3.4", "mocha": "^8.4.0", "request": "^2.88.2" }

chai": "4.3.4" ==> exact version

chai": "^4.3.4" ==> Any latest version greater than or equal to 4.3.4

chai": "~4.3.4" ==> any version of "4" ; minor version or patch can change => major version has t obe "4"

project/node_modules folder contains the downloaded dependecies [ transitive dependecies]

Testing file naming conventions: converter.test.js converter.spec.js

modify package.json: "scripts": { "start" : "node ./src/server.js", "test": "mocha --reporter spec" }

Run the server: npm start

Run the tests: npm test

this executes all files in "test" folder

Need to test Async code

When the project is commited onto git ==> add node_modules to .gitignore

Team members: npm i

makes use of entries in "package.json" and downloads

=================================================================

TypeScript

-g ==> Global ==> any exectuable modules let it go to "global"

npm i -g typescript

downloads in : C:\Users\username\AppData\Roaming\npm

$ tsc

=============================

TypeScript by Microsoft is a superset of JS

introduces static typing for JS

Concept of data types to JS

In JS we declare members as in:

var x = 10;

x = "Smith";

x = true;

let x = 10;

const x = 10;

=========== ECMAScript 5 ECMAScript 6 / ES2105 or 7 /EsNext Babel is a free and open-source JavaScript transcompiler that is mainly used to convert ECMAScript 2015+ code into a backwards compatible version of JavaScript

file.js [ ES6 / ESNext] ==> babel ==> file.js [ ES5 ]

TypeScript Compiler:

file.ts [ contains data types ] ==> tsc file.ts ==> file.js [ code minus data type]

================================

TypeScript data types:

1. Number

let age:number = 10;

age = "a"; // tsc throws error

2. String

let name:string = "Peter";

3. boolean

let flag:boolean = true;

4. array

let elems:number[] = [5,3,22,1];

OR

let elems:Array = [5,3,22,1];

5. enum

enum Color { RED, GREEN, BLUE }

let clr:Color = Color.RED;

6. any

let data:any;

data = "A"; data.toUpperCase(); // allowed data = 10;

Prefer:

let data: number | string;

Functions in TypeScript

HOF ==> Functions which accept functions as argumuents

=============

Task: filter product by category ==> look into interface example

Task ==> implememt Map HOF: https://rxmarbles.com/#map

Try the follwoing transform: 1)each number double it ==> input is numbers 2) each string is converted to upper case

interface in TypeScript

================================

JavaScript build tools: ==> to automate tasks like ==> [traspiling (tsc, babel, )., lint, test, bundle]

1. Grunt Grunt is a JavaScript task runner, a tool used to automatically perform frequent tasks such as minification, compilation, unit testing, and linting.
2. Gulp
3. Webpack https://createapp.dev/

===============

export class Person { constructor(private name:string, private age: number) {

}

}

same as

export class Person { name:string; age: number; constructor( name:string, age: number) { this.name = name; this.age = age; } }

a.ts

let a:number = 10;

b.ts

let a:string = "A";

bundle.js ==> IIFE and module system

let a = (function() { var a = 10; })(); // JS module system

let b = (function() { var a = "A" ; })(); // JS module system

==================================================

Day 3

TypeScript ==> data types; Functions ; Generics; Class and interface; HOF ==> for functional style of programming

tsc ==> npm i -g typescript [ Typescript compiler]

Webpack ==> Bundler, automate bundle by first "transpiling ts to js" and concat files into "bundle.js"

HOF ==> Map implementation

---

Generating tsconfig.json

1. Create a node project npm init --y

2. tsc --init this creates tsconfig.json has information to "tsc" helps us passing commandline arguments to "tsc"

=============================

Decleration / Documentation of TS

Similar to "header" files of "C"

.d.ts contains declaration; no defintions

user.ts [implementation ] ==> user.d.ts [ declarations]

function add(x, y) { return x + y; }

tsc --allowJs --declaration --outDir types a.js

a.d.ts declare function add(x: any, y: any): any;

==========

TypeScript version of "fs", "http" and also unit testing with "jasmine" / "jasmine-ts"

change to directory nodetsexample npm init --y npx tsc --init [OR tsc --init because we installed npm i -g typescript] ==> creates tsconfig.json

npm i typescript @types/node This package contains type definitions for Node.js [ modules like fs, crypto, http, url, ...]

lib.ts

export default add = function() {..}

export sub = function() {..}

other.js

import add, {sub} from './lib';

===========

let p = {"id": 1, "name": "A", "price" : 4567};

let {name, price} = p;

===========

Run the server.ts using ts-node:

tsc + node command: ts-node

npx ts-node ./server.ts

==================

Using Static code analysis using ESLint:

npm i -D eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin

"scripts": { "lint": "eslint . --ext .ts", "test": "echo "Error: no test specified" && exit 1" },

npm run lint

check: https://eslint.org/docs/rules/

Rules eslint .eslintrc

"rules": { 
    "no-case-declarations": 0,
    "no-console": 1 // 0 is no validation; 1 warning ; 2  means error!
  }

============================ Mocha, Jest, Jasmine [ JS Unit Testing framework]

jasmine-ts [ unit testing Typescript]

npm i -D jasmine jasmine-ts @types/jasmine ts-node

npm test

Write Unit testing for filter and map HOF

RTL ==> built on top JEST [ added more custom assertions ]

AngularTestBed ==> built on top of Jasmine [ added more custom assertions]

============================ ISTANBUL Code Coverage https://github.com/istanbuljs/nyc

npm i -D nyc

================================================

.d.ts ==> only Declarations no implementation

1. seperate development and production code

2. if JS libraries needs to be used in typescript we need "its associated .d.ts"

Example: npm i -D @types/node ===> fs.js http.js, url.js ==> can be used in TS files

ESLint, Jasmine-ts

==================================

MySQL

Docker Desktop

docker pull mysql

docker run --name local-mysql –p 3306:3306 -e MYSQL_ROOT_PASSWORD=Welcome123 -d mysql

CONNECT TO A MYSQL RUNNIN CONTAINER

Bash into the running container and run MySQL client.

Bash into the running MySQL container:

$ docker exec -t -i local-mysql /bin/bash

Run MySQL client: $ mysql -u "root" -p

create database nodews; use nodews;

create table products(id int PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100), price double, category VARCHAR(100));

============

========

Day 4:

.d.ts files

@types/node ==> for using Nodejs built-in modules in TypeScript

jasmine-ts for testing TypeScript without transpiling

=========================================================

ORM ==> Object Relational Mapping Objects of program mapped to relational database Type [ class, function] to rdbms table fields mapped to columns of table ORM takes care of DDL and DML operations

Why? 1) Not tightly coupled to a particular database 2) eliminates lots of plumbing code 3) concentrate only on business logic

Node.js popular ORM frameworks

1. sequelize
2. Prisma
3. TypeORM [ supports oracle]

============================

Node.js ORM framework ==> sequelize has support to mysql, postgres, mariadb, MS-SQLServer

http://www.databaseanswers.org/data_models/

create a new folder:

1. npm i mysql2 sequelize typescript

sequelize has typescript support [ no need for @types/sequelize]

2. write connection config file //Product model class Product extends Model {}

   Product.findAll() Product.create() Product.findByPk(1);

   sequelize will generate SQL? ==> uses dialect: "mysql"

   ========

   Promise API ==> Async operation which can be resolved or rejected

   Without promise method calls will be like:

   let data = doTask();

   console.log("blocked!!!");

   // if function was promise based: doTask() .then( (data) => console.log(data), (rej) => console.log(rej)) .catch(err => console.log(err));

   console.log("not blocked!!!"); ============

function doTask() { return new Promise( (resolve,reject) => { setTimeout( () => { reject("Happy I returned!!!"); }, 1000);

}); }

doTask() .then( (data) => console.log(data), (rej) => console.log("Boom: " + rej)) .catch(err => console.log(err));

================

fetch("http://jsonplaceholder.typicode.com/users/1") .then(response => response.json()) .then(data => console.log(data));

using await:

let response = await fetch("http://jsonplaceholder.typicode.com/users/1"); let data = await response.json(); console.log(data);

================= let a = 10;

let p = { a: a }

//import { Op } from 'sequelize/types';

Product.findAll({where: { [Op.and] :[{category: 'mobile'}, {price: 12345}]}}).then( products => { // Product.findAll({where: { category: 'mobile'}}).then( products => { // Product.findAll().then( products => {

sequelize.sync(); // if table exists ==> map to it ; else create table with all constraints

CREATE TABLE IF NOT EXISTS items (itemid INTEGER UNSIGNED auto_increment , amount DOUBLE PRECISION, qty INTEGER, order_fk INTEGER UNSIGNED, product_fk INTEGER UNSIGNED, PRIMARY KEY (itemid), FOREIGN KEY (order_fk) REFERENCES orders (oid) ON DELETE CASCADE ON UPDATE CASCADE, FOREIGN KEY (product_fk) REFERENCES products (id) ON DELETE SET NULL ON UPDATE CASCADE) ENGINE=InnoDB;

===============================

tsconfig.json "sourceMap": true,
// "outFile": "./",
"outDir": "out"

launch.json

{

"version": "0.2.0",
"configurations": [
  {
    "type": "node",
    "request": "launch",
    "name": "Launch Program",
    "program": "${workspaceFolder}/src/api/app.ts",
    "preLaunchTask": "tsc: build - tsconfig.json",
    "outFiles": ["${workspaceFolder}/out/**/*.js"]
  }
]

}

ORM -- sequelize

HasMany HasOne belongsTo belongsToMany

Model ==> CRUD Operations

===================================================

Building RESTful Web services

http module == request:IncommingMessage using this we can identify request.url and perfome tasks

switch(request.url) { case '/': .. case '/products': ... case '/customers': .. }

Prefer Restful webservices frameworks for Node.js [ Middleware framework ] Express, KOA, Restful, HAPI

npm i express cors

npm i -D @types/express @types/cors

POSTMAN

============================

Debug Express Sequeilize application: create tsconfig.json npx tsc --init tsconfig.json "target": "es6", "outDir": "out", "sourceMap": true,

      a.ts => a.map.js =>  a.js

===

launch.json

{

"version": "0.2.0",
"configurations": [
  {
    "type": "node",
    "request": "launch",
    "name": "Launch Program",
    "program": "${workspaceFolder}/src/api/app.ts",
    "preLaunchTask": "tsc: build - tsconfig.json",
    "outFiles": ["${workspaceFolder}/out/**/*.js"]
  }
]

}

Complete this app ==> customer and order ==> routes and controller and service

===============================================================================