Apply a middleware before or after a group of route handlers in Express. No need to change your existing code, just call this function (see demos below).

The usual:

npm install express-group-handlers
npm test   # Be sure to install the dev dependencies if you want to test this module!

var express = require('express')
  , app = express()
  , groupHandlers = require('express-group-handlers');

groupHandlers.setup(app);

app.get('/route1', finalHandler1);
app.get('/route2', finalHandler2);

app.beforeEach(groupHandler, function (app) {
  app.get('/route3', finalHandler3); // GET /route3 will execute groupHandler, then finalHandler3
  app.post('/route4', finalHandler4); // POST /route4 will execute groupHandler, then finalHandler4
  // Note that the syntax is the same than for /route1 and /route2
});

app.listen(3000);

The groupHandlers.setup function augments your Express app with two functions, beforeEach and afterEach. Both work the same way: you supply the middlewares you want to see executed before/after the handlers inside the callback. The callback has one parameter, which is a fake Express app with all router functions (get, post, all etc.). If you give it the same name as your real Express app (as in the example above), no need to change your existing code, just wrap the beforeEach function around it!

// You can have multiple middlewares in beforeEach/afterEach
// You can use arrays of middlewares too
app.beforeEach(gh1, gh2, [gh3, gh4], ..., function (app) {
  // Your routes here
});

// Alternate syntax if you don't want to augment your Express app
// Just don't call groupHandlers.setup and use the functions directly like this
groupHandlers.beforeEach(app, groupHandler, function (app) {
  // Your routes here
});

// Yodawg, I put a beforeEach inside your beforeEach!
app.beforeEach(gh1, function (app) {
  app.get('/route1', finalHandler1); // Executes gh1, then finalHandler1
  app.get('/route2', finalHandler2); // Executes gh2, then finalHandler2
  
  app.beforeEach(gh2, function (app) {
    app.get('/route3', finalHandler3); // gh1, gh2 then finalHandler3
    app.get('/route4', finalHandler4); // gh1, gh2 then finalHandler4
  });
});

Of the above of course works with afterEach. Actually you can even nest beforeEach and afterEach.

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