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Patch for Express to add support for Streamline syntax in Express apps.

Supports Express 2 through 5.


var express = require('express-streamline');
var app = express();
// ... 
app.use(function (req, res, _) {
    if (req.session.userId) {
        req.currentUser = User.getById(req.session.userId, _);
// ... 
app.get('/photos', function (req, res, _) {
    var photos = req.currentUser.getPhotos(_);
    res.render('photos', {
        photos: photos,


npm install express-streamline --save


You can either require() Express normally and then patch it:

var express = require('express');

Or just require() this module, which returns the patched Express for convenience:

var express = require('express-streamline');

Then, you can write any and all Express handlers in Streamline syntax by just replacing next with _.

// middleware handlers: 
app.use(function (req, res, _) { ... });
app.param('user', function (req, res, _, user) { ... });
// route handlers: 
app.get('/:user', function (req, res, _) { ... });'/:user', function (req, res, _) { ... });
// ... (all verbs supported) 
// error handlers: 
app.use(function (err, req, res, _) { ... });

By default, Streamlined middleware handlers will continue to the next middleware, while Streamlined route and error handlers won't. This is generally what you want, but you can specify whether next is called by explicitly returning true or false.

// middleware to blacklist banned IP addresses, 
// but allow all other requests to pass through: 
app.use(function (req, res, _) {
    var isBanned =, _).length > 0;
    if (isBanned) {
        return false;   // end the response 

This module also supports Streamline's smart global context. If present, the context is reset for every request, so data can safely be added to it without affecting other requests.

var globals = require('streamline/lib/globals');
// middleware to set a global `locale` variable on every request, 
// for lower-level modules to use: 
app.use(function (req, res, __) {
    // parse locale... then: 
    globals.context.locale = locale;

If you run into any issues, file a bug!




MIT. © 2012-2015 Aseem Kishore.


TJ Holowaychuk for the awesome Express, and Bruno Jouhier for the awesome Streamline.

Seth Yuan's streamline-express for the inspiration and motivation. streamline-express has supported Express 3 for longer than this module, and it currently also supports more advanced Express 3 features (like passing multiple Streamlined handlers to the same app.verb call). I believe this module has a cleaner API and more robust implementation, however, but I'm biased. =) Both modules get the job done just fine!