express-before-next v1.0.1

Express Before Next

Combining several Express apps and routers together is useful, but often changes to the request and response are leaked down the router chain. This plugin provides a small API for cleaning up when the next() method is called on the router.

Install

npm install express-before-next

Usage

Call attachBeforeNext(router) on any Express Router or Application instance. This will monkey patch the .handle() method on these objects. A req.beforeNext() is attached to the request, pass it functions to be called on clean up. Keep in mind this method are only called if next is called.

const express = require("express");
const attachBeforeNext = require("express-before-next");

function createHomeRoute() {
  const router = express();

  // monkey patch this router
  attachBeforeNext(router);

  router.use(function(req, res, next) {
    // set state on the request that should be cleaned up
    res.locals.foo = "bar";

    // clean up state before going to the next router
    req.beforeNext(() => {
      delete res.locals.foo;
    });
  });

  router.get("/", function(req, res) {
    res.render("home");
  });

  return router;
}

const bigapp = express();
bigapp.use(createHomeRouter());

// when these routes get called, res.locals won't bleed in from above
bigapp.use(otherRoutes());