1.约束数组
interface IMyArray {
[index: number]: number
}
//正确
let arr:IMyArray = [1,2,3]
//错误
let arr:IMyArray = [1,2,'']
2.约束函数
interface ISearchFunc {
//(参数:类型,.....):返回值类型
(a: string, b:string): boolean
}
const fun1:ISearchFunc = function(a:string, b:string):boolean {}