joaogolias

const a = 3;
if (a < 2) {
  console.log('is less than 2')
}

joaogolias

{
  "name": "backend-for-dummies-examples",
  "version": "1.0.0",
  "main": "main.js",
  "license": "MIT",
  "dependencies": {
    "typescript": "^3.1.4"
  },
  "devDependencies": {
    "ts-node": "^7.0.1",

joaogolias

{
  "name": "backend-for-dummies-examples",
  "version": "1.0.0",
  "main": "main.js",
  "license": "MIT",
  "dependencies": {
    "typescript": "^3.1.4"
  },
  "devDependencies": {
    "ts-node": "^7.0.1",

joaogolias

console.log('Hello World')

joaogolias

const myAge: number = 20
let myDescirption: string = 'Hello'

if (myAge > 0) {
    myDescirption += ', I am ' + myAge.toString()
} else {
    myDescirption += ', I have just been born'
}

joaogolias

function isEven(num: number): boolean {
    return num % 2 === 0
}

isEven(20) // => true
isEven(11) // => false

joaogolias

const isPositive = function(value: number) : boolean {
    return value > 0
}

isPositive(1) // => true
isPositive(-20) // => false

joaogolias

let comparison: boolean
comparison = 1 == true // => true
comparison = 1 === true // => false

comparison = 0 == false // => true
comparison = 0 === false // => false

comparison = '1' == 1 // => true
comparison = '1' === 1 // => false

joaogolias

const multiply = (factor1: number, factor2: number) : number => {
    return factor1 * factor2
}

multiply(1,2) // => 2
multiply(3,4) // => 12

joaogolias

const validateUser = (name?: string, email: string, password: string) => {
    if (!name) {  // if(name === undefined) {
        throw new Error('invalid_name')
    }

    if (email.indexOf('@') -== -1) {
        throw 'invalid_email'
    }

    if (password.length < 6) {