ts官方入门

https://www.tslang.cn/docs/handbook/typescript-in-5-minutes.html

环境搭建

npm install -g typescript

测试环境是否成功

新建 greeter.ts

function greeter(person) {
  return "Hello, " + person;
}

let user = "Jane User";

document.body.innerHTML = greeter(user);

编译一下 会生成同名的但是结尾是 js 的文件

tsc greeter.ts

1.添加类型注解 【和 java 一样】

function greeter(person: string) {
  return "Hello, " + person;
}

let user = "Jane User";

document.body.innerHTML = greeter(user);

现在把 user 改为数组：

let user = [1, 2, 3];

再次编译就报错了：

虽然编译报错了，但是 js 文件还是生成了。

TypeScript提供了静态的代码分析，它可以分析代码结构和提供的类型注解。

2.使用接口

接口描述对象，指明对象里面有哪些键

interface Person {
  firstName: string;
  lastName: string;
}

function greeter(person: Person) {
  return "Hello, " + person.firstName + " " + person.lastName;
}

let user = { firstName: "Jane", lastName: "User" };

document.body.innerHTML = greeter(user);

3.接口描述类

class Student {
  fullName: string;
  constructor(public firstName, public middleInitial, public lastName) {
    this.fullName = firstName + " " + middleInitial + " " + lastName;
  }
}

interface Person {
  firstName: string;
  lastName: string;
}

function greeter(person: Person) {
  return "Hello, " + person.firstName + " " + person.lastName;
}

let user = new Student("Jane", "M.", "User");

document.body.innerHTML = greeter(user);