TypeScript variable

Variable

TypeScript covers JavaScript grammer.

let

let flag: boolean = false;

let is variable identifier, it’s like swift, but not const.
We can also use var same as javascript
const

const x = 111;

TypeScript type

• boolean
• number
• string
• array
• class
• interface
• enum
• function

javascript also has type, but it’s ambiguous.
Some are from Java, C# etc…

Number

let decimal: number = 11;
let hex: number = 0xf1ad;
let binary: number = 0b1212;
let octal: number = 0o544;

String

let firstname: string = "kotori";
firstname = 'umi';

Array

let list: number[] = [1,2,3];

let nlist: Array<number> = [1,2,3];

let slist: string[] = ['Honoka', 'Kotori', 'Umi'];

Tuple

let x: [string, number];
x = ["xxxx", 10];
//x = [10, "xxxx"];  Error!!!!

Any

Any type is O.K. Umm.. finally, var

let umm: any = 1;
umm = "I am string";