TypeScript接口

1、关键字：interface

interface IUser {name: stringage: number
}let user: IUser = {name: "张三"， age: 22};
console.log(user);// {name: "张三"， age: 22}

2、接口的继承

        关键字：extendes

interface IUser {name: stringage: number
}let user: IUser = {name: "张三"， age: 22};
console.log(user);// {name: "张三"， age: 22}// 接口可以继承
interface IStudent extends IUser {}let student: IStudent = {name: "李四"， age: 18};console.log(student);
// {name: "李四"， age: 18}

3、接口的可选参数

        关键字： ？

interface IUser {name: stringage: number
}let user: IUser = {name: "张三"， age: 22};
console.log(user);// {name: "张三"， age: 22}// 接口可以继承
// CET6?: 代表CET6是可选参数，可有可无，而CET4参数则必须得有
interface IStudent extends IUser {CET4: booleanCET6?: boolean
}let student1: IStudent = {name: "李四"， age: 18, CET4: true};
let student2: IStudent = {name: "李四"， age: 18, CET4: true, CET6: false};console.log(student1);
// {name: "李四"， age: 18, CET4: true}console.log(student2);
// {name: "李四"， age: 18, CET4: true, CET6: false}

4、接口的只读属性

        关键字：readonly

interface IUser {name: stringage: number
}let user: IUser = {name: "张三"， age: 22};
console.log(user);// {name: "张三"， age: 22}// 接口可以继承
interface IStudent extends IUser {readonly DNA: stringCET4: booleanCET6?: boolean
}let student: IStudent = {name: "李四", age: 18, DNA: "aaaa", CET4: true};console.log(student);
// {name: "李四"， age: 18, CET4: true} // CET6是可更改的属性
student.CET6 = true;console.log(student);
// {name: "李四"， age: 18, CET4: true, CET6: true} // 报错 DNA字段是不可修改的，是只读属性
student.DNA = "ddddddd";

5、函数类型接口

// 接口的目的重在约束
interface IFunc {(name: string): void
}let f: IFunc = (a: string): void => {console.log(a);
}f("aa");// aa

6、可索引类型接口

interface IIndex {[index: string]: string
}let index: IIndex = {username: "张三", nickName: "zhangsan"}；console.log(index);// {username: "张三", nickName: "zhangsan"}

7、类类型的接口

// 接口重在于约束
interface User {name: stringage: numbersayInfo(): void
}class Student implements User {name: stringage: numbersayInfo(): void {console.log("姓名: " + this.name);console.log("年龄: " + this.age);}constructor(name: string, age: number) {this.name = name;this.age = age;}
}let student: Student = new Student("张三", 18);
student.sayInfo();// 姓名: 张三
// 年龄: 18