typeScript数据类型

1// 布尔类型
2let isDone: boolean = false;
3// 数字类型 所有数字都是浮点数 number
4let decLiteral: number = 6;
5let hexLiteral: number = 0xf00d;
6let binaryLiteral: number = 0b1010;
7let octalLiteral: number = 0o744;
8// 字符串
9let username: string = "bob";
10username = "smith";
11//  可以使用模版字符 定义多行文本和内嵌表达式
12let uname: string = "gene";
13let age: number = 37;
14let sentence: string =
15  "hello, my name is ${name} I'll be ${age+1} years old next month.";
16
17// 数组  元素类型后接上[]
18let list: number[] = [1, 2, 3];
19let list1: Array<number> = [1, 2, 3];
20
21// 元组
22let x: [string, number];
23x = ["hello", 10];
24console.log(x[0].substr(1));
25
26//枚举
27enum Color {
28  Red,
29  Green,
30  Blue
31}
32let c: Color = Color.Green;
33
34//任意值
35let notSure: any = 4;
36notSure = "maybe a string instead";
37notSure = false;
38
39notSure.ifItExists();
40notSure.toFixed();
41
42// 空值 没有任何类型
43function warnUser(): void {
44  alert("This is my warning message");
45}
46let unusable: void = undefined;
47// null undefined
48let u: undefined = undefined;
49let n: null = null;
50
51// Never 永不存在的值类型
52function error(message: string): never {
53  throw new Error(message);
54}
55
56function fail() {
57  return console.error("something failed ");
58}
59
60//Object 表示非原始类型 除 number,sting, boolean, symbol, null underfined之外的类型
61declare function create(o: object|null):void;
62
63create({prop:0});
64create(null);