索引签名
  1. interface StringArray{
  2.     [index:number]:string
  3. }
  1. interface NumberDictionary{
  2.     [index:string]:number
  3.     length:number
  4.     //name:string 报错 它和[index:string]重合了， 但是类型却不一致
  5.     //[index:string]:number|string //使用联合类型解决
  6. }
  8. const person:NumberDictionary = {
  9.     length:1,
  10.     qqb:111,
  11.     21:123
  12. }

索引签名 不管是 数字类型还是string 它们是一样，也就是当你使用了string的索引签名后 不再被允许使用number类型

继承
  1. interface BasicAddress{
  2.   name?:string
  3.   street:string
  4. }
  5. interface AddressWithUnit extends BasicAddress{
  6.   unit:string
  7. }
  9. interface Colorful {
  10.   color: string;
  11. }
  13. interface Circle {
  14.   radius: number;
  15. }
  17. interface ColorfulCircle extends Colorful, Circle {}
交叉类型
  1. interface Colorful {
  2.   color: string;
  3. }
  4. interface Circle {
  5.   radius: number;
  6. }
  8. type ColorfulCircle = Colorful & Circle;
  10. function draw(circle: Colorful & Circle) {
  11.   console.log(`Color was ${circle.color}`);
  12.   console.log(`Radius was ${circle.radius}`);
  13. }