Writing CasperJS modules

As of 1.1, CasperJS relies on PhantomJS’ native require() function internally though it had to be patched in order to allow requiring casper modules using their full name, eg. require('casper').

So if you plan to write your own modules and use casperjs’ ones from them, be sure to call the patchRequire() function:

// my module, stored in universe.js
// patching phantomjs' require()
var require = patchRequire(require);

// now you're ready to go
var utils = require('utils');
var magic = 42;
exports.answer = function() {
    return utils.format("it's %d", magic);


When using CoffeeScript global.require must be passed to patchRequire() instead of just require:

require = patchRequire global.require

utils = require 'utils'
magic = 42
exports.answer = ->
  utils.format "it's ${magic}"

From your root casper script:

var universe = require('./universe');
console.log(universe.answer()); // prints "It's 42"

New in version 1.1..


CasperJS allows using nodejs modules installed through npm. Note that since CasperJS uses it’s own JavaScript environment, npm modules that use node-specific features will not work under CasperJS.

As an example, let’s install the underscore library:

$ npm install underscore

Then, require it like you would with any other nodejs compliant module:

var _ = require('underscore');
var casper = require('casper').create();
var urls = _.uniq([

casper.start().eachThen(urls, function(response) {
  this.thenOpen(response.data, function(response) {


Finally, you’ll probably get something like this:

$ casperjs npm-underscore-test.js
CasperJS documentation | CasperJS 1.1.0-DEV documentation