函数
参数类型
ts
function sum(a: number, b: number) {}
const sum = (a: number, b: number) => {}返回值类型
ts
function sum(a: number, b: number): void {}
const sum = (a: number, b: number): void => {}可选参数
当我们认为参数不是必要传的时候我们可以使用?
ts
const sum = (a: number, b: number, c?: number): void => {}默认参数
ts
const sum = (a: number, b: number, c: number = 5): void => {}剩余参数
ts
const sum = (a: number, b: number, ...restList: number[]): void => {}Type 关键字
type 关键字能让我们提取一个公共类型
ts
// before
const createUser = (user: { name: string; age: number }): void => {}
const updateUser = (user: { name: string; age: number }): void => {}
// after
type userType = {
name: string
age: number
}
const createUser = (user: userType): void => {}
const updateUser = (user: userType): void => {}