TS基础用法
对象
// 定义一个 Dictionary ，key 是 string 类型，value 是 number 类型
type RouterInfo = {
name: string;
age: number;
};
type HandleInfo = {
[key: string]: RouterInfo;
};
const data: HandleInfo = {
a: {
name: "a",
age: 1,
},
b: {
name: "b",
age: 2,
},
};
console.log(data);
type HandelType = "primary" | "secondary";
// 定义一个 Dictionary ，key 是 HandelType 中的值 ，value 是 RouterInfo 类型
type HandleInfo1 = {
[key in HandelType]: RouterInfo;
};
函数
let add: (a: number, b: number) => number = (a, b) => a + b;
type handleFunc = (a: number, b: number) => number;
let add1: handleFunc = (a, b) => a + b;
数组
type Router = {
name: string,
age: number,
};
function getRouterInfo(router: Array<Router>) {
router.forEach((item) => {
console.log(item.name);
});
}
function getRouterInfo1(router: Router[]) {
router.forEach((item) => {
console.log(item.name);
});
}
function getRouterInfo2(router: Array<Router | string>) {
router.forEach((item) => {
console.log(item);
});
}
function getRouterInfo3(router: (Router | string)[]) {
router.forEach((item) => {
console.log(item);
});
}
联合类型
let value: string | number = "Hello";
交叉类型
type A = { name: string };
type B = { age: number };
type C = A & B;
枚举类型
enum Direction {
LEFT = "left",
RIGHT = "right"
}
类型转换
let someValue: any = "Hello, TypeScript!";
let strLength: number = (someValue as string).length;
this
class Counter {
count = 0;
increment(): this {
this.count++;
return this;
}
}
let counter = new Counter();
counter.increment().increment(); // 可以链式调用
Pick
使用已经存在的定义中的一部分
interface User {
name: string;
age: number;
no: number;
}
type BasicType = Pick<User, "name" | "age">;
const user: BasicType = {
name: "jack",
age: 18,
};
