Service provider for Node.JS without pain with Dependency Injection Container, dependency registration, and configuration.
- You can use it at any place of your application without rewrite your applications architecture or other preparations or initializations.
- Each dependency can be class or function.
- You can override your dependencies for unit testing without hack standard Node.JS require mechanism.
- You can use TypeScript or JavaScript.
import { shared } from "node-shared";
// It is can be service or shared state or cross requests data
class Users {
async getById(id) {
...
}
}
const sharedUsers = () => shared(Users);
// And with express for example
app.get("/user/:id", async (req, res) => {
const users = sharedUsers();
res.json(await users.getById(req.params.id));
});
And
import { shared } from "node-shared";
// ...
class Db { /* ... */ }
class Server { /* ... */ }
// ...
// Inject dependencies using a shared function and class properties
export default class App {
db = shared(Db);
server = shared(Server);
// ...
start() {
this.db.init();
// ...
}
}
// index.ts
new App().start(); // You can create an instance directly as usually class
You can use mock
to provide mocks into your dependencies.
import { mock } from "node-shared";
import { Users, Api } from "./shareds";
test("Users service should call api service inside", async () => {
const apiMock = mock(Api, {
getUserById: jest.fn();
});
const users = new Users();
await users.getById("John");
expect(apiMock.getUserById).toHaveBeenCalledWith("John");
});
If you use Jest for unit testing you need to add some code to your jest.config.json
file.
// jest.config.json
{
...
setupFilesAfterEnv: [
"node-shared/jest"
],
...
}
This code means that after each test cached shareds instances will be clear. For another testing frameworks, you need call free
after each test case manually for cleanup cached instances of dependencies.
afterEach(require("node-shared").free);
shared
Returns instance of your dependency. Each dependency can be class or function.
- For class. The class will be instantiated once and cached
- For function. The function will be called and result cached
const db = shared(Db);
mock
Define resolved value for any dependency.
const mockedDb = mock(Db, {
connect: jest.fn()
});
shared(Db).connect();
expect(mockedDb.connect).toHaveBeenCalled();
free
Clean all cached shared instances. It's needed for testing usually. Has no parameters.
free()
npm i node-shared
Enjoy and Happy Coding!