一、条件语句

二、函数

1、有名函数

	function add(x:number, y:number):number {
		return x + y;
	}

2、匿名函数

	let add = function (x:number, y:number):number {
		return x + y;
	}

• 函数可选参数

	function buildName(firstname: string, lastname?:string) {
		if (lastname) {
			return firstname + lastname;
		} else {
			return firstname;
		}
	}

	let result1 = buildName('wang');
	let result2 = buildName('wang', 'xiaoming');

• 函数剩余参数

	function buildName(a: string, ...restparams:string[]) {
		return a + restparams.join('');
	}

	let result1 = buildName('wang');
	let result2 = buildName('a', 'b', 'c');

3、箭头函数，匿名函数简写，省略了function关键字，可以将箭头函数赋值给变量；

（a, b, ...c）=> {}
let res = （a, b, ...c）=> {}

三、类

class Person {
	private name:string // 定义私有属性
	private age:number
	
	constructor(name:string, age:number){ // 初始化构造函数
		this.name = name;
		this.age = age;
	}
	
	public getPersonInfo() { // 公共方法
	 return `my name is ${this.name} and is ${age}岁`;
	}
}
let xiaoming = new Person('xiaoming', 18);
xiaoming.getPersonInfo()

四、继承

class Employee extends Person {
	private department:string;
	constructor(name:string, age:number, department:string) {
		super(name,age); // 继承
		this.department = department;
	}
	public getEmployeeInfo():string {
		return this.getPersonInfo() + `and work in ${this.department}`
	}
}
let person2 = new Employee('xiaoming', 18, 'tech');
person2.getPersonInfo()
person2.getEmployeeInfo()

五、模块

六、迭代器