如何在打字稿 2.0 / 3.0 中添加自定义“类型”

Question

According to this article typings system for typescript 2.0 has changed and so it is not clear how to attach custom typings now. Should I always create NPM package for that?

Thank you in advance!

Answer 1

You can create local custom typings just for your project, where you can declare types for JS libraries. For that, you need to:

1. Create directory structure to keep your type declaration files so that your directory structure looks similar to this:

    . ├── custom_typings │   └── some-js-lib │   └── index.d.ts └── tsconfig.json

2. In the index.d.ts file, add a declaration for your JS library:

    declare module 'some-js-lib' { export function hello(world: string): void }

3. (Optional: skip if you have TypeScript >= 4.x) Add a reference to this type declaration in the compilerOptions section of your tsconfig.json :

    { "compilerOptions": { ... "typeRoots": ["./node_modules/@types", "./custom_typings"] }, ... }

4. Use the declared module in your code:

    import { hello } from 'some-js-lib' hello('world!')

Answer 2

Assuming you have your external js package installed under node_modules, I think there are two options:

• provide a typescript declaration file in the package , and add a reference to it:

   // node_modules/secret-package/index.d.ts export interface SecretInterface { // ¯\\_(ツ)_/¯ } 

  And reference the typings file in the package.json:

   // node_modules/secret-package/package.json { ..., "typings": "./index.d.ts", ..., } 

• augment the module in a declaration file of your project

   // index.d.ts declare module 'secret-package' { interface SecretInterface { // ¯\\_(ツ)_/¯ } }