class Woman extends Human { private gender: number = 0; public constructor(name: string, age: number) { super(name, age); console.log(this.age); } } const woman = new Woman('Alice', 18); // -> Property 'age' is private and only accessible within class 'Human'. 1. 2. 3. 4....
return this._language; } set language(value: string) { this._language = value; } get tasks() { return this._tasks; } set tasks(value: string[]) { this._tasks = value; } } const dev = new Developer(); // ⛔️ Error: Property '_language' is private // and only accessible ...
typeof 是一个在 JavaScript 中已经存在的操作符,用于获取一个值的类型。在 TypeScript 中,typeof 操作符也可以用于获取一个值的类型,并将其作为一个类型注解或类型声明使用。 代码语言:typescript AI代码解释 letx=10;lety:typeofx;// y 的类型为 number 在上述代码中,typeof x 返回 number 类型,并将其...
class Derived1 extends Base { protected x: number = 5; } class Derived2 extends Base { f1(other: Derived2) { other.x = 10; } f2(other: Base) { other.x = 10; // Property 'x' is protected and only accessible through an instance of class 'Derived2'. This is an instance of cla...
class BadGreeter { name: string; // Property 'name' has no initializer and is not definitely assigned in the constructor. } class GoodGreeter { name: string; constructor() { this.name = "hello"; } } 注意,字段需要在构造函数自身进行初始化。TypeScript 并不会分析构造函数里你调用的方法,进而...
class MyClass { private static x = 0;}console.log(MyClass.x);// Property 'x' is private and only accessible within class 'MyClass'.静态成员也可以被继承：class Base { static getGreeting() { return "Hello world"; }}class Derived extends Base { myGreeting = Derived.getGreeting(...
type Foo = number | { someProperty: number } 当你需要继承或实现时,使用 interface 代码语言:javascript 代码运行次数:0 运行 AI代码解释 interface Foo { foo: string; } interface FooBar extends Foo { bar: string; } class X implements FooBar { foo: string; bar: string; } 风格指南 使用箭头函...
// error Property 'age' does not exist on type 'typeof Parent'.class Child extends Parent {constructor(age: number) {super(age);console.log(super.age); // error Only public and protected methods of the base class are accessible via the 'super' keyword.console.log(super.getAge());}}...
class Point { x = 0 y = 0 } const pt = new Point() // Prints 0, 0 console.log(`${pt.x}, ${pt.y}`)就像const、 let 和var 一样,一个类属性的初始化器将被用来推断其类型。const pt = new Point(); pt.x = "0";--strictPropertyInitialization strictPropertyInitialization设置控制是否...
四、 获取值的类型 / 类型保护 typeof 1 //示例1:获取数据类型2let O4 = {name:"lily",age:12}3type I4 =typeofO445class O5 {6uid:number|null=null7constructor(){}8getName(){}9getAge(){}1011}12let obj =newO5()13type I6 =typeofobj1415 ...