d-ts声明文件
https://stackoverflow.com/questions/21247278/about-d-ts-in-typescript
// 区别?
export declare const thing: number;
export const thing: number;
https://www.typescriptlang.org/dt/search?search=
https://github.com/DefinitelyTyped/DefinitelyTyped
npm管理
在node_modules的@types模块下

import calculator from 'calculate'
calculator('plus',[1,2])
calculator.plus([1,2])
type IOperator = 'plus' | 'minus'
interface ICalculator{
(operator: IOperator, numbers: number[]): number;
plus: (numbers: number[]) => number;
minus: (numbers: number[]) => number;
}
declare const calculator: ICalculator
export default calculator
