类型别名

type Plustype = (x: number, y: number) => number;
let sum: Plustype = (x: number, y: number) => {
  return x + y;
};
type stringOrNumber = string | number;
let a: stringOrNumber = 123;
let b: stringOrNumber = "abc";

字面量类型

let a: "up" | "down" | "left" | "right"
type Direction = "up" | "down" | "left" | "right"
let b: Direction

交叉类型

interface IName {
  name: string;
}
interface IAge {
  age: number;
}
type IPerson = IName & IAge; // 这个有点像继承多个接口的意思
let zhangSan: IPerson = {
  name: "zhangSan",
  age: 18,
};
class Lisi implements IName, IAge {
  name: "lisi";
  age: 18;
}