TypeScript对象类型

# TypeScript对象类型

常说的函数、{}、数组、类

# Object

object

object表示非原始类型，也就是除number，string，boolean，symbol，null或undefined之外的类型。

let object: object;
object = 1; // 报错
object = "a"; // 报错
object = true; // 报错
object = null; // 报错
object = undefined; // 报错
object = {}; // 编译正确

1
2
3
4
5
6
7

Object

大 Object 代表所有拥有 toString、hasOwnProperty 方法的类型。所以所有原始类型、非原始类型都可以赋给 Object(严格模式下 null 和 undefined 不可以)

let bigObject: Object;
object = 1; // 编译正确
object = "a"; // 编译正确
object = true; // 编译正确
object = null; // 报错
ObjectCase = undefined; // 报错
ObjectCase = {}; // ok

1
2
3
4
5
6
7

{}

{} 空对象类型和大 Object 一样也是表示原始类型和非原始类型的集合

# 类

通过 Class 关键字来定义一个类

class Person {
  name: string;
  age: number;
  constructor(name: string, age: number) {
    this.name = name;
    this.age = age;
  }
  sayHi(): void {
    console.log(`Hi, ${this.name}`);
  }
}

1
2
3
4
5
6
7
8
9
10
11

# 函数

# 函数声明

function add(x: number, y: number): number {
  return x + y;
}

1
2
3

# 函数表达式

const add = function(x: number, y: number): number {
  return x + y;
}

1
2
3

# 接口定义函数

interface Add {
  (x: number, y: number): number;
}

1
2
3

# 可选参数

function add(x: number, y?: number): number {
  return y ? x + y : x;
}

1
2
3

# 默认参数

function add(x: number, y: number = 0): number {
  return x + y;
}

1
2
3

# 剩余参数

function add(...numbers: number[]): number {
  let sum = 0;
  for (let i = 0; i < numbers.length; i++) {
    sum += numbers[i];
  }
  return sum;
}

1
2
3
4
5
6
7

# 函数重载

使用相同名称和不同参数数量或类型创建多个方法的一种能力。
```
function add(x: number, y: number): number;
function add(x: string, y: string): string;
function add(x: any, y: any): any {
  return x + y;
}
```
1
2
3
4
5
注意：

函数重载真正执行的是同名函数最后定义的函数体在最后一个函数体定义之前全都属于函数类型定义不能写具体的函数实现方法只能定义类型

参数是对象

interface User{
    name:string
    age:number
}
function add(user:User):User{
    return user
}
add({name:"hhh",age:17})

1
2
3
4
5
6
7
8

this（TS可以定义this的类型，在js中无法使用，必须是第一个参数定义this的类型）

interface Obj{
    user:number[]
    add:(this.Obj,num:number)=>void
}
let obj:Obj = {
    user:[1,2,3]
    add(this:Obj,num:number){
        this.user.push(num)
    }
}
obj.add(4)

1
2
3
4
5
6
7
8
9
10
11

# 内置对象

# ECMAScript 的内置对象

Boolean、Number、string、RegExp、Date、Error

let b: Boolean = new Boolean(1)
console.log(b)
let n: Number = new Number(true)
console.log(n)
let s: String = new String('hhh')
console.log(s)
let d: Date = new Date()
console.log(d)
let r: RegExp = /^1/
console.log(r)
let e: Error = new Error("error!")
console.log(e)

1
2
3
4
5
6
7
8
9
10
11
12

# DOM 和 BOM 的内置对象

let body: HTMLElement = document.body;
let allDiv: NodeList = document.querySelectorAll('div');

//读取div 这种需要类型断言 或者加个判断应为读不到返回null
let div:HTMLElement = document.querySelector('div') as HTMLDivElement
document.addEventListener('click', function (e: MouseEvent) {
    
});
//dom元素的映射表
interface HTMLElementTagNameMap {
    "a": HTMLAnchorElement;
    "abbr": HTMLElement;
    "address": HTMLElement;
    "applet": HTMLAppletElement;
    "area": HTMLAreaElement;
    "article": HTMLElement;
    "aside": HTMLElement;
    "audio": HTMLAudioElement;
    "b": HTMLElement;
    "base": HTMLBaseElement;
    "bdi": HTMLElement;
    "bdo": HTMLElement;
    "blockquote": HTMLQuoteElement;
    "body": HTMLBodyElement;
    "br": HTMLBRElement;
    "button": HTMLButtonElement;
    "canvas": HTMLCanvasElement;
    "caption": HTMLTableCaptionElement;
    "cite": HTMLElement;
    "code": HTMLElement;
    "col": HTMLTableColElement;
    "colgroup": HTMLTableColElement;
    "data": HTMLDataElement;
    "datalist": HTMLDataListElement;
    "dd": HTMLElement;
    "del": HTMLModElement;
    "details": HTMLDetailsElement;
    "dfn": HTMLElement;
    "dialog": HTMLDialogElement;
    "dir": HTMLDirectoryElement;
    "div": HTMLDivElement;
    "dl": HTMLDListElement;
    "dt": HTMLElement;
    "em": HTMLElement;
    "embed": HTMLEmbedElement;
    "fieldset": HTMLFieldSetElement;
    "figcaption": HTMLElement;
    "figure": HTMLElement;
    "font": HTMLFontElement;
    "footer": HTMLElement;
    "form": HTMLFormElement;
    "frame": HTMLFrameElement;
    "frameset": HTMLFrameSetElement;
    "h1": HTMLHeadingElement;
    "h2": HTMLHeadingElement;
    "h3": HTMLHeadingElement;
    "h4": HTMLHeadingElement;
    "h5": HTMLHeadingElement;
    "h6": HTMLHeadingElement;
    "head": HTMLHeadElement;
    "header": HTMLElement;
    "hgroup": HTMLElement;
    "hr": HTMLHRElement;
    "html": HTMLHtmlElement;
    "i": HTMLElement;
    "iframe": HTMLIFrameElement;
    "img": HTMLImageElement;
    "input": HTMLInputElement;
    "ins": HTMLModElement;
    "kbd": HTMLElement;
    "label": HTMLLabelElement;
    "legend": HTMLLegendElement;
    "li": HTMLLIElement;
    "link": HTMLLinkElement;
    "main": HTMLElement;
    "map": HTMLMapElement;
    "mark": HTMLElement;
    "marquee": HTMLMarqueeElement;
    "menu": HTMLMenuElement;
    "meta": HTMLMetaElement;
    "meter": HTMLMeterElement;
    "nav": HTMLElement;
    "noscript": HTMLElement;
    "object": HTMLObjectElement;
    "ol": HTMLOListElement;
    "optgroup": HTMLOptGroupElement;
    "option": HTMLOptionElement;
    "output": HTMLOutputElement;
    "p": HTMLParagraphElement;
    "param": HTMLParamElement;
    "picture": HTMLPictureElement;
    "pre": HTMLPreElement;
    "progress": HTMLProgressElement;
    "q": HTMLQuoteElement;
    "rp": HTMLElement;
    "rt": HTMLElement;
    "ruby": HTMLElement;
    "s": HTMLElement;
    "samp": HTMLElement;
    "script": HTMLScriptElement;
    "section": HTMLElement;
    "select": HTMLSelectElement;
    "slot": HTMLSlotElement;
    "small": HTMLElement;
    "source": HTMLSourceElement;
    "span": HTMLSpanElement;
    "strong": HTMLElement;
    "style": HTMLStyleElement;
    "sub": HTMLElement;
    "summary": HTMLElement;
    "sup": HTMLElement;
    "table": HTMLTableElement;
    "tbody": HTMLTableSectionElement;
    "td": HTMLTableDataCellElement;
    "template": HTMLTemplateElement;
    "textarea": HTMLTextAreaElement;
    "tfoot": HTMLTableSectionElement;
    "th": HTMLTableHeaderCellElement;
    "thead": HTMLTableSectionElement;
    "time": HTMLTimeElement;
    "title": HTMLTitleElement;
    "tr": HTMLTableRowElement;
    "track": HTMLTrackElement;
    "u": HTMLElement;
    "ul": HTMLUListElement;
    "var": HTMLElement;
    "video": HTMLVideoElement;
    "wbr": HTMLElement;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129

# 定义Promise

function promise():Promise<number>{
   return new Promise<number>((resolve,reject)=>{
       resolve(1)
   })
}
 
promise().then(res=>{
    console.log(res)
})

1
2
3
4
5
6
7
8
9

# 代码雨案例

let canvas = document.querySelector('#canvas') as HTMLCanvasElement
let ctx = canvas.getContext('2d') as CanvasRenderingContext2D
canvas.height = screen.availHeight; //可视区域的高度
canvas.width = screen.availWidth; //可视区域的宽度
let str: string[] = 'XMZSWSSBXMZSWSSBXMZSWSSBXMZSWSSBXMZSWSSB'.split('')
let Arr = Array(Math.ceil(canvas.width / 10)).fill(0) //获取宽度例如1920 / 10 192
console.log(Arr);
 
const rain = () => {
    ctx.fillStyle = 'rgba(0,0,0,0.05)'//填充背景颜色
    ctx.fillRect(0, 0, canvas.width, canvas.height)//背景
    ctx.fillStyle = "#0f0"; //文字颜色
    Arr.forEach((item, index) => {
        ctx.fillText(str[ Math.floor(Math.random() * str.length) ], index * 10, item + 10)
        Arr[index] = item >= canvas.height || item > 10000 *  Math.random() ? 0 : item + 10; //添加随机数让字符随机出现不至于那么平整
    })
    console.log(Arr);
    
}
setInterval(rain, 40)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

具体来源 (opens new window)

#TS

上次更新: 2024/08/14, 04:14:33

← TypeScript基础类型 TyprScript类型推论→

TypeScript对象类型