接口是用来描述对象性状的
interface School{
readonly type:String, //readonly表示只读,不可更改的属性
age:Number,
adress?:String //?代表非必要
}
let BeiDa:School={
type:'Univercity',
age:100,
adress:'beijing'
}
接口是可以扩展的
Interface SchoolGrade extends School{
grade:String
[xxx:String]:any //表示其它任意属性的任意值
}
let sannianerban:SchoolGrade={
...BeiDa,
grade:'3年2班',
guys:30,
row:5,
col:6
}
类型断言 (相当于类型强制转换)
let grade2:School=({
name:'QingHua',
age:105,
adress:'BeiJing',
lessons:'高等数学'
}) as School