TypeScript—语法简介

TypeScript官方指导文档：https://www.tslang.cn/docs/home.html

基本类型

变量声明

使用let和const两个关键字声明变量，具体形式如下：

let user = "Jane User";

接口定义

interface SquareConfig {
  color?: string;//？代表可选属性
  width?: number;
  readonly x: number;//readonly 表示只读属性
  readonly y: number;
    
}

function createSquare(config: SquareConfig): { color: string; area: number } {
  let newSquare = {color: "white", area: 100};
  if (config.clor) {
    // Error: Property 'clor' does not exist on type 'SquareConfig'
    newSquare.color = config.clor;
  }
  if (config.width) {
    newSquare.area = config.width * config.width;
  }
  return newSquare;
}

let mySquare = createSquare({color: "black"});

类定义

abstract class Department {

    constructor(public name: string) {
    }

    printName(): void {
        console.log('Department name: ' + this.name);
    }

    abstract printMeeting(): void; // 必须在派生类中实现
}

class AccountingDepartment extends Department {

    constructor() {
        super('Accounting and Auditing'); // 在派生类的构造函数中必须调用 super()
    }

    printMeeting(): void {
        console.log('The Accounting Department meets each Monday at 10am.');
    }

    generateReports(): void {
        console.log('Generating accounting reports...');
    }
}

let department: Department; // 允许创建一个对抽象类型的引用
department = new Department(); // 错误: 不能创建一个抽象类的实例
department = new AccountingDepartment(); // 允许对一个抽象子类进行实例化和赋值
department.printName();
department.printMeeting();
department.generateReports(); // 错误: 方法在声明的抽象类中不存在

相关知识点：

class关键字，继承关键字extends，公有public、私有private与受保护protected的修饰符，只读属性修饰符readonly、静态属性static、getters/setters存取器、抽象类abstract、

函数定义

// Named function
function add(x, y) {
    return x + y;
}

// Anonymous function
let myAdd = function(x, y) { return x + y; };

相关知识点：

有名函数、匿名函数、可选参数、默认参数、剩余参数、