@microbackend/plugin-express

Microbackend plugin for express.js.

Installation

This plugin is automatically included if you had initialized a microbackend project with:

npx microbackend init --template express

To install it as a standalone dependency:

npx microbackend plugin add @microbackend/plugin-express

Usage

For illustration purposes, create the following files in your project:

• src/extension/express/route/route1.ts:

import { IMicrobackendInitFunction } from "@microbackend/plugin-express";

export default ((): IMicrobackendRouteCreator => {
  return () => {
    return {
      handler: async (_req, res) => {
        res.json({ value: 1 });
      },
      method: "get",
      route: "/route1",
    };
  };
})();

• src/extension/express/route/middleware1.ts:

import { IMicrobackendMiddlewareCreator } from "@microbackend/plugin-express";

export default ((): IMicrobackendMiddlewareCreator => {
  return () => {
    return {
      handler: (req, _res, next) => {
        console.log(req);
        next();
      },
    };
  };
})();

Then, in your main application entry file:

import { createExpressApplication } from "@microbackend/plugin-express";
import express from "express";

export default createExpressApplication().then((app) => {
  app.use(((err, _req, res, _next) => {
    res.status(err.status || 500).json({ error: err.message });
  }) as express.ErrorRequestHandler);

  const port = process.env["PORT"] || 3001;

  app.listen(port, () => {
    console.log("Started example server on port", port);
  });
});

Now, your Express app will automatically have a middleware that logs all requests, and a request handler registered for route /route1.

In short, the extension patterns supported by this plugin are:

• IMicrobackendRouteCreator, supported by extension/express/route: A function type that creates an Express route. The handler option can either be a function or an express.Router instance.

• IMicrobackendMiddlewareCreator, supported by extension/express/middleware: A function type that creates an Express middleware.

For more information on extension patterns, please have a look at @microbackend/plugin-core.