Wondering what’s next for npm?Check out our public roadmap! »


1.3.0 • Public • Published

Build Status Test Coverage Code Climate Dependency Status



Declarative Express Application Wiring

express-jefferson is a microlibrary for declaratively describing RESTful services.

// main.js
var express = require('express'),
    jefferson = require('express-jefferson'),
    app = express(),    
    conf = {
        proxies: [
                name: 'Logger',
                init (delegate) {
                    return (req, res, next) => {
                        console.log("invoking middleware function");
                        delegate(req, res, next);
        params: {
            beerId: (req, res, next, id) => {
                req.beer = getBeerById();
        routes: {
            getBeerList: {
                method: 'GET',
                path: '/beers',
                middleware: [
            getBeer: {
                method: 'GET',
                path: '/beers/:beerId',
                middleware: [
jefferson(app, conf);


  • routes - (required) - A map of routes by name. Each object in the map describes an endpoint to be wired. These endpoints must contain an HTTP method, a path, and an array of middleware functions.
  • aliases: (optional) - A map of alias-name to handler chain. Routes may use these aliases in lieu of repeated function groups.
  • proxies: (optional) - An array of proxy objects invoked around all middleware functions in order. Each proxy object should have an init() function that accepts a delegate middleware function and returns a new middleware function.
  • params: (optional) - A map of path-parameter name to resolver functions.
  • pre: (optional) - (object) Boilerplate section of pre-middleware functions
  • post: (optional) - (object) Boilerplate section of post-middleware functions

Boilerplate Config Sections (pre/post):

  • all: (optional) - An array of middleware to be applied to all endpoints.
  • safe: (optional) - An array of middleware to be applied to all safe endpoints (GET, HEAD, OPTIONS).
  • unsafe: (optional) - An array of middleware to be applied to all unsafe endpoints (not GET, HEAD, OPTIONS).
  • method: (optional, object) - On object of method-name to handler list.

Proxies provided in Jefferson

Promise-Based Middleware Proxy


This proxy accepts promise-based middleware (middleware that accepts two arguments) and wraps them in a promise chain before invoking next().

Config Options:

  • haltCondition (optional) - a predicate function that accepts the request and response. If it returns a truthy value, then the middleware chain will be halted.

Trace Logger Middleware Proxy


This proxy logs invocations of middleware using the debug library.

Config Options:

  • logger (optional) - the name of the debug logger to use. Default is "jefferson:trace-logger"



npm i [email protected]





Last publish


  • avatar
  • avatar