tbd - notes taken while learning Javascript

javascript_notes.js

console.log('Hello World')

//#region variables

/*
Cannot be a reserved keyword
Cannot start with a number
Cannot contain space or hyphen
Are case sensitive
*/

// declare a variable
let userName = 'Jake'
console.log(userName)

let firstName = 'Test1'
let FirstName = 'Test1'
// ^ these are different because of case

let interestRate = 0.3
interestRate = 1
console.log(interestRate)

// this will not work because constant
const interestRateConst = 0.3
// interestRateConst = 2

//#region primitives

// string, number, boolean, undefined, null
let myName = 'Jake' //string
let age = 38 //number
let isApproved = true //boolean
let zeName = undefined //undefined
let selectedColor = null

//#endregion

//#endregion

//#region reference types

// object, array, function

// object
let example = {} //object literal
let person = {
    name: 'Jake',
    age: 38
}
console.log(person)
// dot notation
person.age
person.name = 'Joey'
// bracket notation
person['name'] = 'Mary'

// array
let someColors = [] // empty array
let selectedColors = ['red', 'blue'] // empty array
selectedColors[2] = 'green'
console.log(selectedColors[0])

// functions
function greet(firstName, lastName) {
    console.log('Hello ' + firstName + ' ' + lastName)
}
greet('Jake', 'Smith')

// calculates a value
function square(number) {
    return number * number
}
let number = square(2)
console.log(number)

//#endregion