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import Breadcrumb from '../../../components/Breadcrumb'

title: Interface 接口 date: 2023-01-15 authors: Chengzihan tags: [TypeScript]

Interface 接口可以用来定义对象的类型。

功能

  • 描述对象的形状（Shape）
  • 对类（Class）进行抽象
  • Duck Typing（鸭子类型），即如果一个对象有某些属性，那么就可以认为它是某种类型

接口定义

interface Person {
  name: string;
  age: number;
}
 
let tom: Person = {
  name: 'Tom',
  age: 25,
};

倘若不一致：

interface Person {
  name: string;
  age: number;
}
 
let tom: Person = {
  name: 'Tom',
};

那么会报错：

Type '{ name: string; }' is not assignable to type 'Person'.
  Property 'age' is missing in type '{ name: string; }' but required in type 'Person'.

可选属性

当然，也可以定义可选属性：

interface Person {
  name: string;
  age?: number;
}
 
let tom: Person = {
  name: 'Tom',
};

由于可选属性的存在，那么就不会报错了。

只读属性

interface Person {
  readonly id: number;
  name: string;
  age?: number;
}
 
let tom: Person = {
  id: 89757,
  name: 'tom',
  age:10,
};
 
tom.id = 9527;

上述代码会报错：

Cannot assign to 'id' because it is a read-only property.
02.basictype04.fuctions