typescript interface类型(接口类型)

• 接口定义对象的类型

interface Person {
  name: string;
  age: number;
}

let tom: Person = {
  name: 'tom',
  age: 20,
};

• 可选属性，用 ? 标记

interface Person2 {
  name: string;
  age?: number;
}

let tom2: Person2 = {
  name: 'tom',
};

• 只读属性，用 readonly 标记

interface Person3 {
  readonly name: string;
  age?: number;
}

let per: Person3 = { name: 'tom' };
per.name = 'tom'; //无法为“name”赋值，因为它是只读属性

interface Add1 {
  (x: number, y: number): number;
}
let add1: Add1 = (a, b) => 'result' + a + b;