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var expressShare = require("express-share")

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express-share v0.1.1

Client-side code sharing and management for Express

Express-share is an extension for the Express web framework. It takes browser script management by the balls. It handles all the scripts-tags which are sent to the browser.

The grand scheme is that you can seamlessly write server and client-side code. You can embed client-side code in to your Node.js files! It should be trivial to change code execution from the server to the client. Also function and variable sharing is a breeze.

It is also possible to specify a folder from which client-side only Javascript/CoffeeScript files will be automatically loaded and sent to the browser.

Express-share is also aware of development and production modes. In development mode it makes sure that caching won't get in your way etc. In production mode it takes all the Javascript code and concatenates them in to a single .js file, minifies it using Uglifyjs and caches it in memory.


npm install express-share


Lets start with a small example code to get you excited!

var createServer = require("express").createServer;
var addCodeSharingTo = require("express-share").addCodeSharingTo;

function isEmail(s) { return !! s.match(/.\w+@\w+.\w/); }

var app = createServer(); addCodeSharingTo(app);

// Add external script to browser app.shareUrl("");

// Share isEmail with the browser app.share({isEmail: isEmail});

// This function will be actually executed in the browser! app.exec(function(){ jQuery(document).ready(function(){ $("#send").submit(function(e){ if ( !isEmail($("#email").val()) ) { e.preventDefault(); alert("Bad email!"); } }); }); });

app.get("/", function(req, res){ res.share({variable: "You are at application root!"});

// You can also add client code by request basis res.exec(function(){ alert(variable); });

res.render("index.jade"); });


And to achieve all this you only need to call renderScriptTags helper in the head tag of your layout template.

Code sharing API

addCodeSharingTo(Express server object)

Extends Express server object and response objects with share and exec methods.

  • returns Express server object

server.share([namespace regexp, ] map of variables)

Shares almost any given Javascript object with the browser. Will work for functions too, but make sure that you will use only pure functions. Scope or the context won't be same in the browser. Cannot handle objects with circular references.

Code will be shared where the regexp matches on request.url or on every page if it is omitted.

server.share will be set only once on server startup. So you can only use this to share general purpose functions and variables. Use response.share to share variables more dynamically.

  • returns shared object


server.share({onEveryPage: "This string will be found on every page"});
server.share(/^\/subpage.*/, {subPageVariable: "This string is found only from /subpage and its sub pages"});

server.exec([namespace regexp, ] function)

Executes the given function at page load in the browser as soon as it is loaded if the given namespace regexp matches. If namespace is omitted the function will be executed on every page.

Variables shared with server.share() can be found from the parent scope or from from the context of the function (ie. this-variable).

Code will be shared where the regexp matches on request.url or on every page if it is omitted.

  • returns shared function



server.exec(/^\/subpage.*/, function()

server.shareFs([namespace regexp, ] path to a script file)

Share given script file from filesystem with the browser. Can be .js or .coffee file.

Code will be shared where the regexp matches on request.url or on every page if it is omitted.

  • returns undefined


server.shareFs(/^\/subpage.*/, __dirname + "myscript.js");

server.shareUrl(url to a .js file | array of urls)

Executes given Javascript URL in the browser as soon as it is loaded. Will be executed before any other code.

  • returns undefined

response.share(map of variables)

Same as server.share(), but shared object(s) will be dynamically sent to browser only with this response as inline script.

  • returns shared object


Same as server.exec(), but the given function will be executed only with this response as inline script.

Function can access variables shared with response.share() from parent scope, but not the variables shared by server.share(). Those can be accessed from the context of the function.

  • returns shared function

Dynamic helper renderScriptTags

Really Express also registers an essential dynamic helper function, renderScriptTags, for embedding all the script-tags. Just include ouput of it as raw html in your layout template.



!!! 5
    title= title
    h1= title
    #container !{body}

Script order

Scripts will be rendered in following order in the browser.

  1. server.shareUrl()
  2. Scripts automatically loaded from the filesystem in alphabetical order
  3. server.shareFs()
  4. server.share()
  5. server.exec()
  6. server.shareFs() namespaced
  7. server.share() namespaced
  8. server.exec() namespaced
  9. response.share()
  10. response.exec()

Production mode concatenates 2-5 levels into a single request. Rest will be served as inline scripts.


Code sharing adds an extra setting, clientscripts to Express. It allows you to specify a directory where client-side only scripts can be loaded. They will be automatically sent to browser in alphabetical order by the renderScriptTags helper. You can also use CoffeeScript files there. They will be automatically compiled to Javascript.

Default is process.cwd() + "/clientscripts"


Modify it by using set.

app.set("clientscripts", __dirname + "/clientscripts");


  • Sanitize script order
  • Add tests for script order
  • Do not inline namespaced scripts?


Questions and suggestions are very welcome

  • Esa-Matti Suuronen
  • esa-matti [aet] suuronen dot org
  • Epeli @ freenode/IRCnet
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