5.⾃定义类型
<p>自定义类型，可以更灵活的限制类型</p>
<pre><code>// 性别的枚举
enum Gender {
Male,
Female
}
// ⾃定义⼀个年级类型（⾼⼀、⾼⼆、⾼三）
type Grade = 1 | 2 | 3
// ⾃定义⼀个学⽣类型
type Student = {
name:string,
age:number,
gender:Gender,
grade:Grade
}
// 定义两个学⽣变量：s1、s2
let s1:Student
let s2:Student
s1 = {name:'张三',age:18,gender:Gender.Male,grade:1}
s2 = {name:'李四',age:18,gender:Gender.Female,grade:2}</code></pre>