1212
1313 类的实例, 通过 ` new ` 实例化
1414
15- - 面向对象三大特性
15+ - [ 面向对象三大特性] ( #面向对象的三大特性 )
1616
1717 👇👇👇 [ Here] ( #面向对象的三大特性 )
1818
19- - 存取器
19+ - [ 存取器] ( #存取器 )
2020
2121 ` getter ` : 对属性的取值行为
2222
2323 ` setter ` : 对属性的赋值行为
2424
25- - 修饰器
25+ - [ 修饰符 ] ( #修饰符 )
2626
2727 ` public ` : 修饰** 公有** 属性和方法 ` (默认) ` ，可以在任何地方被访问到
2828
2929 ` protected ` : 修饰** 保护** 属性和方法，在子类中也是允许被访问的
3030
3131 ` private ` : 修饰** 私有** 属性和方法，不能在声明它的类的外部访问
3232
33- - 抽象类
33+ - [ 静态属性 & 方法 ` static ` ] ( #静态属性-方法 )
34+
35+ ** 只能** 通过类访问的属性 ` or ` 方法。
36+
37+ - [ 抽象类] ( #抽象类 )
3438
3539 抽象类` (absctract) ` 是供其他类继承的基类，** 抽象类不允许被实例化** 。抽象类中的抽象方法** 必须在子类中被实现**
3640
37- - 接口
41+ - [ 接口 ] ( #把类当接口使用 )
3842
3943 不同类之间公有的属性或方法，可以抽象成一个接口。接口可以被类实现 ` (implements) ` 。** 一个类只能继承自另一个类，但是可以实现多个接口**
4044
4650
4751### 继承
4852
49- 子类获取父类的所有属性和行为` (父类中用 private 修饰的变量和方法。) `
53+ 子类获取父类的所有属性和行为` (除了父类中用 private 修饰的变量和方法) ` 。
5054
5155### 多态
5256
53- 同一操作作用于不同对象，可以有不同的解释，产生不同的执行结果 。
57+ ** 多种不同的实现方式 ** 即为多态, 它允许方法重名，参数或返回值可以是父类型传入或返回 。
5458
5559## 类的好处
5660
57- 对象提供了模型化和信息隐藏的好处。类提供了[ 可重复使用性] ( https://zh.wikipedia.org/w/index.php?title=可重複使用性&action=edit&redlink=1 ) 的好处。自行车制造商一遍一遍地重用相同的蓝图来制造大量的自行车。软件程序员用相同的类，即相同的代码一遍一遍地创建对象。
61+ - 对象提供了模型化和信息隐藏的好处。
62+
63+ - 类提供了[ 可重复使用性] ( https://zh.wikipedia.org/w/index.php?title=可重複使用性&action=edit&redlink=1 ) 的好处。
5864
5965## 使用
6066
61- #### 抽象类
67+ ### public(公有) & protected(保护) & private(私有) 修饰符
68+
69+ #### public
70+
71+ 修饰** 公有** 属性和方法 ` (默认) ` ，可以在任何地方被访问到
6272
6373``` ts
64- abstract class Boy {
74+ class Animal {
75+ public name: string ;
76+ public constructor (theName : string ) { this .name = theName ; }
77+ public move(distanceInMeters : number ) {
78+ console .log (` ${this .name } moved ${distanceInMeters }m. ` );
79+ }
80+ }
81+ ```
82+
83+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAECCB2BLAtmE0DeAoavoAcBXAIxEWGnjGQFMAuaCAFwCdF4BzAbhzyNPLRgAe3jMWhYE2EsAFEwAWNAHLV6jVuw4BKTNEWIIAOiq1oAXn1LVtLtAC+vXPzIVkwgG41ZAE0NMweGAaAEl4AFkaJhoWCAZ4QmRiGN1sPHShUQhhEBojEGEOWQADABIMA2NTGntody8faHK-ZkDgsMjo2PtkI2LtHnTHeyA )
84+
85+ #### protected
86+
87+ 修饰** 保护** 属性和方法，在子类中也是允许被访问的
88+
89+ ``` ts
90+ class Person {
91+ protected name: string ;
92+ constructor (name : string ) { this .name = name ; }
93+ }
94+
95+ class Employee extends Person {
96+ private department: string ;
97+
98+ constructor (name : string , department : string ) {
99+ super (name )
100+ this .department = department ;
101+ }
102+
103+ public getElevatorPitch() {
104+ return ` Hello, my name is ${this .name } and I work in ${this .department }. ` ;
105+ }
106+ }
107+
108+ let rainy = new Employee (" Rain" " 120"
109+ console .log (rainy .getElevatorPitch ());
110+ console .log (rainy .name ); // 错误
111+ ```
112+
113+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAEAKCmAnCB7AdtA3gKGn6ADoigC7zBkAm0aYAtvAFzQQmICWaA5gNy77B0rRAFcKKRAApaDZsM5cAlFmgkAFuwgA6GfGgBeGvXg9oAX2wXsoSDACidAiBQBPeHvgAPMmkowEyOhY-HhE7ABuYGTQlPAEYIgkDGgkcmwKfCHQgmjCYiQS0sZpHNwANDFxCUnwKSUKyjj4zSwiBEhFDIpZzeqaWrHxickkBpVDNSl8zVbNBCIARiDswNBc8CR2IPCRBYiw7CTAapKNPfiIGyKIGAAGABLwIM4VdC5GDNCa0AAkmH3aXRmaBgXzQACS0AA7hIANZfDB-AEDKrDWokMxaW7TfAWKzbUaIMCcd6GNDwKHQBxOVzuSQAIgASsS0PSKvSAIwAJgADPTFHwcqhtlpnFxJESSVp1pttrsJAcjidFALrEIUCKxRKWS4dMYBdAAPSG6CATFTAPfRQA )
114+
115+ #### private
116+
117+ 修饰** 私有** 属性和方法，不能在声明它的类的外部访问
118+
119+ ``` ts
120+ class Animal {
121+ private name: string ;
122+ constructor (theName : string ) { this .name = theName ; }
123+ }
124+
125+ class Cat extends Animal {
126+ constructor () { super (" Cat"
127+ }
128+
129+ class Employee {
130+ private name: string ;
131+ constructor (theName : string ) { this .name = theName ; }
132+ }
133+
134+ let animal = new Animal (" Dog"
135+ let cat = new Cat ();
136+ let employee = new Employee (" Rain120"
137+
138+ animal = cat ;
139+ animal = employee ; // 错误: Animal 与 Employee 不兼容.
140+ ```
141+
142+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAECCB2BLAtmE0DeAoavoAcAnRANzABcBTaeMZSgLmgnOPgHMBuHPYAe3gtCAV2Dk+hABTkAFpQBydRs1aIOASkzRZiCADpa9aAF5tcxfU7QAvlltZQkGAGEK0SgA8q8ACYwEKGiYPLj8gqyi4lKaGMzC+JRSAESu5EnqVrb2jlDQAKLI+CB8AJ6U1Nh4BMRkVDRKTEJqXCHQYUKREtLmDSps7DFmugZKJmYKSpl2WFgglOTQYEio6KbwlADucMtokkkAInzs6dxzC8Bua5vQqZIZs-PuhcVl1FdbBUWl5XsASmBqACMACYAAwnGZLQKrNoUbhQlZjSjPb6UKwAenR0EAmKmAe+imAFEYA4OXyKNe0EAsHKAH0VAJ3aeiAA )
143+
144+ ### readonly 修饰符
145+
146+ #### 属性
147+
148+ 将属性设置为只读的。 ** 只读属性必须在声明时或构造函数里被初始化** 。
149+
150+ ``` ts
151+ class Octopus {
152+ readonly name: string ;
153+ readonly numberOfLegs: number = 8 ;
154+ constructor (theName : string ) {
155+ this .name = theName ;
156+ }
157+ }
158+ let dad = new Octopus (" Man with the 8 strong legs"
159+ dad .name = " Man with the 3-piece suit" // 错误! name 是只读的.
160+ ```
161+
162+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAEDywBcD2AHArjA3gKGn6ATgKZgAmSAdiAJ7QVgC2RAXNBAgQJYUDmA3LnzEylGnTQMARkQKwAZgBkiPCKwoTpBaAF5oADgH5owSuwJpESLQAoEACyIA5RizYduPAJTQcRo-c4IADp6Jh1oeycXQ3wAX2x4kCIEaFIycIoiAHc4S3QIawAiAFkwCmgsznsIh303AkoeaCSVQs8BNNIQl3CSsoqquxqiaABmAFoUTiJgEYg0KsK+IA )
163+
164+ #### 参数
165+
166+ ``` ts
167+ class Octopus {
168+ readonly numberOfLegs: number = 8 ;
169+ constructor (readonly name : string ) {
170+ }
171+ }
172+ ```
173+
174+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAEDywBcD2AHArjA3gKGn6ATgKZgAmSAdiAJ7QVoC2ARkQbAGYAyRA5hAFx1GLAtAC80ABwBuXPmCUICAmkRICACmJlKNOmAZFBSggEsKPAJTQc+aAF9s9oA )
175+
176+ ### 存取器
177+
178+ ``` ts
179+ class Employee {
180+ private _fullName: string = ' '
181+
182+ constructor (_fullName : string ) {}
183+
184+ get fullName(): string {
185+ return this ._fullName ;
186+ }
187+
188+ set fullName(newName : string ) {
189+ this ._fullName = newName ;
190+ }
191+ }
192+
193+ let employee = new Employee (' Rainy'
194+ employee .fullName = " Rain120"
195+ console .log (employee .fullName )
196+ ```
197+
198+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAECiC2AHEB7AngUw9A3gKGkOkQCcBLANzABdsB9AMwFcQQA5MeDALmgmvIA7AObQAvNADkkgNx48ASGApB-Ek2DUUJABSMW7Tjz4CyIgJS4AvvKLRhGatGasOXHed5qzo-HbskjkwkgtDUABZkEAB0+q5GcnY2BEQQjs4Gbhg6ghgA7llepha4Kf5hkTFxhlzi0LkFCWXQNskg6RhIqJjYEg1wXehYOpIASmBmaJLmcp3IQxjRLjW90ABE42YAjABMAAxrcsqqKO3RqMI6c91YS5lG5kA )
199+
200+ ** Note:**
201+
202+ - 存取器要求你将编译器设置为输出 ` ECMAScript 5 ` 或更高。 不支持降级到` ECMAScript 3 ` 。
203+ - ** 只带有 ` get ` 不带有 ` set ` 的存取器** 自动被推断为 ` readonly ` 。 这在从代码生成 ` .d.ts ` 文件时是有帮助的，因为利用这个属性的用户会看到不允许够改变它的值。
204+
205+ ### 静态属性 & 方法
206+
207+ 只能通过类来访问，实例不行
208+
209+ ``` ts
210+ class Boy {
211+ static handsome: boolean = true ;
212+ constructor (public name : string ) {}
213+ static isHandsome() {
214+ return this .handsome ;
215+ }
216+ }
217+
218+ let rain120 = new Boy (' Rain120'
219+ console .log (Boy .handsome );
220+ console .log (Boy .isHandsome );
221+ console .log (rain120 .handsome ); // Property 'handsome' is a static member of type 'Boy'
222+ console .log (rain120 .isHandsome ); // Property 'isHandsome' is a static member of type 'Boy'
223+ ```
224+
225+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAEBCD2BPaBvAUNaEAuZsEthoALMAOwBMJ4BbAUwC5oAjeeEO86AXmmwCcArnQDcGaMHhkcQ4Nnj8AFAAdBzEIWhkw9JjPxkA5gEpUAX3E48m-BAAS5KrTqLT6TJn51sg-mT7EtgB0pJTU9GKYFhZoHNjQ-GAGAIwATAAMPFp0AO5wSIoA5ABKSWRp6YXGYpLS7HRBIPCGigiIIY7hdMZotdQcjc2tSEG2DmHOPX31gy2JKRkdE-RTUv0NTXNlFaP2nZNAA )
226+
227+ ### 继承
228+
229+ ``` ts
230+ class Boy {
65231 handsome: boolean ;
66232 name: string ;
67233
@@ -70,7 +236,7 @@ abstract class Boy {
70236 this .handsome = handsome ;
71237 }
72238
73- abstract isHandsome(): boolean {}
239+ isHandsome() {}
74240}
75241
76242class Mine extends Boy {
@@ -83,7 +249,72 @@ const mine = new Mine('Rain120', true);
83249console .log (mine )
84250```
85251
252+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAEBCD2BPaBvAUNaALMA7AJhPALYCmAXNAEbzwil4DcG0uYZlEALgE4CWuAObNMLYPFzceAV2Bd4PABRsO0KQMEAabHkIkK1WvTwBKVC0xcsfCADoVpaAF5W7UiMzQrN2zgJEyZx1-fQ8AXxY0AEgbAAldANJFMxQIiLRQSBgAWQFHUgAPLlJ-OCRzTDiE-WSKzx5SLmkeXC9rOz89MnC0dPFJLmhiPKDcUgB3aFyxxQByACUwAQBGACYABlntXmlSE2Z+onpbEHhBRWGxkyA )
253+
254+ #### 多态
255+
256+ ``` ts
257+ export function trace(cities : any , prop ? : string , enterBreakPoint ? : boolean ): void ;
258+
259+ export function trace(cities : any , enterBreakPoint ? : boolean ): void ;
260+
261+ export function trace(enterBreakPoint ? : boolean ): void ;
262+
263+ export function trace(... args : any []): void {
264+ }
265+ ```
266+
267+ [ Playground] ( https://www.typescriptlang.org/play?#code/KYDwDg9gTgLgBAMwK4DsDGMCWEVxlAQzWAAo1MtgBnALjgJQE8AaOMKCMAfjqv0xQBzVsBQxgUAEJRgBANYAFCAJg84AIwgQANrJQBKOgDdlAEwDcAKEuhIsRKgzZc+IqXKVa9JiLETpsorKYmqaOnqGcCaYFta20PDI6Fg4eITEJKLiUjLySiqhWroMkdGxNuAJDsnOaW4kAHRNBFCCXgyMANoAuqVmcADelgC+QA )
268+
269+ ### 抽象类
270+
271+ ``` ts
272+ abstract class Boy {
273+ handsome: boolean ;
274+ name: string ;
275+
276+ constructor (name : string , handsome : boolean ) {
277+ this .name = name ;
278+ this .handsome = handsome ;
279+ }
280+
281+ abstract isHandsome(): boolean ;
282+ }
283+
284+ class Mine extends Boy {
285+ isHandsome() {
286+ return this .handsome ;
287+ }
288+ }
289+
290+ const = new Mine (' Rain120' true );
291+ console .log (mine );
292+ ```
293+
294+ [ Playground] ( https://www.typescriptlang.org/play?#code/IYIwzgLgTsDGEAJYBthjAgQgewJ4IG8AoBBAC2ADsATMbAWwFMAuBEbbZRqgbhIUrAmrSFACWlAOZ9S-WNkqiArvGxQAFIOEJREyQBpyVWgxZsOXKgEpC-UhDJiwAOi2MEAXgFDGM0ggcnZwoaOiZPI1DTPwBffn5QUThEJwAJYzDGdStWdk5uSj44ohQ0DABZCXdGAA8IRlCsPFtSNIzTbJb-KEYIJShKAMcXEJMmWKJi+UVEeiqIykYAdwRKxfUAcgAlYAkARgAmAAYNw2glRis+abouZ2RsSXU5xaugA )
295+
296+ ### 把类当接口使用
297+
298+ ``` ts
299+ class Boy {
300+ handsome: boolean = true ;
301+ }
302+
303+ class Girl {
304+ beatiful: boolean = true ;
305+ }
306+
307+ enum Gender {
308+ ' MALE'
309+ ' FEMALE'
310+ }
311+
312+ interface Person extends Boy , Girl {
313+ gender: Gender ;
314+ }
315+ ```
86316
317+ [ Playground] ( https://www.typescriptlang.org/play?#code/MYGwhgzhAEBCD2BPaBvAUNaALMA7AJhPALYCmAXNAEbzwil7QC80ALgE4CupA3GgL5o0oSDADiAS3YhUGag1YSAZpxCUadBrmZsuvAUNK5OxaGKP5S7WZgDkAWQCCAGQCitgDRzbAMVdO3WwM0CVxWKyUwYFJoAAUrIm1SAA9wghgERA8zKRl0TABzCytKcwIrPn4gA )
87318
88319## 快来耍耍啊
89320
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