基础类型

数字 number

const level: number = 6;

字符串 string

cosnt name: string: "huangping"

布尔值 boolean

const isBoy: boolean = true;

数组 array

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

元组 Tuple

let x: [string, number];
x = ['hello', 10];

枚举 enum

enum Color {
  Red,
  Green,
  Yellow,
}
let c: Color = Color.Green;

任意值 any

let a: any = 4;
a = 'huangping';

空值 void

function voidFunc(): void {
  console.log('void');
}

Null 和 Undefined

Never

类型断言

let someValue: any = 'this is a string';
let strLength: number = (<string>someValue).length;
or;
let strLength: number = (someValue as string).length;

接口

用 interface 关键字定义一个接口

• 当接属性可选时，可在属性名字定义后面加上一个?符号
• 只读属性，可在属性名前用 readonly 来指定

interface person {
  name: string;
  age: number;
  address?: string;
  readonly sex: string;
}