Types

// #1 
var name: string;

// #2
function greetText(name: string): string {
    return "Hello " + name;
}

Built-in types

String

var name: string = 'Felipe';

Number

In TypeScript, all numbers are represented as floating point

var age: number = 36;

Boolean

var married: boolean = true;

Array

Array<type>
type[]

// #1
var jobs: Array<string> = ['IBM', 'Microsoft', 'Google'];
var jobs: string[] = ['Apple', 'Dell', 'HP'];

// #2
var jobs: Array<number> = [1, 2, 3];
var jobs: number[] = [4, 5, 6];

Enums

Used to provide names to numeric values

// #1
enum Role {Employee, Manager, Admin};
var role: Role = Role.Employee; // 0

// #2
enum Role {Employee = 3, Manager, Admin};
var role: Role = Role.Employee; // 3, Manager = 4, Admin = 5

// #3 - set individual values
enum Role {Employee = 3, Manager = 5, Admin = 7};
var role: Role = Role.Employee;

// #4 - look with value
enum Role {Employee, Manager, Admin};
console.log('Roles: ', Role[0], ',', Role[1], 'and', Role[2]);

Any

any is the default type if we omit typing for a given variable

var something: any = 'as string';
something = 1;
something = [1, 2, 3];

Void

Using void means there’s no type expected

function setName(name: string): void {
    this.name = name;
}