typescript数据类型

时间：2022-08-09 08:25:39
// 布尔类型

let isDone: boolean = false;

// 数字类型 所有数字都是浮点数 number

let decLiteral: number = 6;

let hexLiteral: number = 0xf00d;

let binaryLiteral: number = 0b1010;

let octalLiteral: number = 0o744;

// 字符串

let username: string = "bob";

username = "smith";

//  可以使用模版字符 定义多行文本和内嵌表达式

let uname: string = "gene";

let age: number = 37;

let sentence: string =

  "hello, my name is ${name} I'll be ${age+1} years old next month.";

// 数组  元素类型后接上[]

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

let list1: Array<number> = [1, 2, 3];

// 元组

let x: [string, number];

x = ["hello", 10];

console.log(x[0].substr(1));

//枚举

enum Color {

  Red,

  Green,

  Blue

}

let c: Color = Color.Green;

//任意值

let notSure: any = 4;

notSure = "maybe a string instead";

notSure = false;

notSure.ifItExists();

notSure.toFixed();

// 空值 没有任何类型

function warnUser(): void {

  alert("This is my warning message");

}

let unusable: void = undefined;

// null undefined

let u: undefined = undefined;

let n: null = null;

// Never 永不存在的值类型

function error(message: string): never {

  throw new Error(message);

}

function fail() {

  return console.error("something failed ");

}

//Object 表示非原始类型 除 number,sting, boolean, symbol, null underfined之外的类型

declare function create(o: object|null):void;

create({prop:0});

create(null);

　　

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