TypeScript Basic Types

let name: string = 'John'; # string type
let age: number = 25; # number type
let isActive: boolean = true; # boolean type
let data: null = null; # null type
let value: undefined = undefined; # undefined type

let numbers: number[] = [1, 2, 3]; # array of numbers
let names: Array<string> = ['John', 'Jane']; # generic syntax

let tuple: [string, number] = ['John', 25]; # fixed-length array

let value: any = 'hello'; # any type (avoid)
let data: unknown = 10; # unknown type (safer)

function log(): void { # returns nothing
    console.log('Hello');
}
function error(): never { # never returns
    throw new Error('Error');
}

let value: unknown = 'hello';
let length: number = (value as string).length; # type assertion
let length2 = (<string>value).length; # alternative syntax