Basic Types

TypeScript

                    
let myString: string;
let myNum: number;
let myBool: boolean;
let myVar: any;

let strArr: string[];
//let strArr: Array;
let numArr: number[];
let boolArr: boolean[];
let anyArr: any[];

let tuple: [string, number];

//other types: void, null, undefined, enum and generic

myString = "Hello";
myNum = 42;
myBool = true;
myVar = false;

strArr = ["hello", "World"];
numArr = [1,2,3];
boolArr = [true, false, true];
anyArr = [ true, 'Steve', 86]

tuple = ['Bob', 24]; //what is declared must match but more can be added

JavaScript

                    
var myString;
var myNum;
var myBool;
var myVar;

var strArr;
//var strArr = [];
var numArr;
var boolArr;

var tuple;

myString = "Hello";
myNum = 42;
myBool = true;
myVar = false;

strArr = ["hello", "World"];
numArr = [1, 2, 3];
boolArr = [true, false, true];

tuple = ['Bob', 24];

Functions

TypeScript

                    
function getSum(num1:number, num2:number):number{
    return num1 + num2;
}

console.log(getSum(6,4));

JavaScript

                    
function getSum(num1, num2) {
    return num1 + num2;
}
console.log(getSum(6, 4));

Interfaces

An interface is basically creating your own custom "type"

TypeScript

                    
interface Todo{
    title: string;
    text: string;
}

function showTodo(todo: Todo){
    console.log(todo.title+': '+todo.text);
}

let  myTodo = {title:'Trash', text: 'Take out trash'};

showTodo(myTodo);

JavaScript

                    
function showTodo(todo) {
    console.log(todo.title + ': ' + todo.text);
}
var myTodo = { title: 'Trash', text: 'Take out trash' };
showTodo(myTodo);

Classes

TypeScript

                    
class user {
    name: string;
    private email: string;
    protected age: number;

    constructor(name: string, email: string, age: number){
        this.name = name;
        this.email = email;
        this.age = age;
    }

    register(){
        console.log(this.name+" is now registered");
    }
}

let steve = new user("Steve", "steve@gmail.com", 34);
steve.register();

JavaScript

                    
var user = (function () {
    function user(name, email, age) {
        this.name = name;
        this.email = email;
        this.age = age;
    }
    user.prototype.register = function () {
    console.log(this.name + " is now registered");
    };
    return user;
})();
var steve = new user("Steve", "steve@gmail.com", 34);
steve.register();