Develop Reference

How to check if element exists using Cypress.io

How to check if element is present or not, so that certain steps can be performed if element is present. Else certain different steps can be performed if element is not present.
I tried something like below but it didn't work:
Cypress.Commands.add('deleteSometheingFunction', () => {
cy.get('body').then($body => {
if ($body.find(selectors.ruleCard).length) {
let count = 0;
cy.get(selectors.ruleCard)
.each(() => count++)
.then(() => {
while (count-- > 0) {
cy.get('body')
// ...
// ...
}
});
}
});
});
I am looking for a simple solution, which can be incorporated with simple javascript
if else block or then() section of the promise
Something similar to Webdriver protocol's below implementions:
driver.findElements(By.yourLocator).size() > 0
check for presenece of element in wait
Kindly advise. Thanks

I'll just add that if you decide to do if condition by checking the .length property of cy.find command, you need to respect the asynchronous nature of cypress.
Example:
Following condition evaluates as false despite appDrawerOpener button exists
if (cy.find("button[data-cy=appDrawerOpener]").length > 0) //evaluates as false
But this one evaluates as true because $body variable is already resolved as you're in .then() part of the promise:
cy.get("body").then($body => {
if ($body.find("button[data-cy=appDrawerOpener]").length > 0) {
//evaluates as true
}
});
Read more in Cypress documentation on conditional testing

it has been questioned before: Conditional statement in cypress
Thus you can basically try this:
cy.get('header').then(($a) => {
if ($a.text().includes('Account')) {
cy.contains('Account')
.click({force:true})
} else if ($a.text().includes('Sign')) {
cy.contains('Sign In')
.click({force:true})
} else {
cy.get('.navUser-item--account .navUser-action').click({force:true})
}
})

cypress all steps are async ,, so that you should make common function in commands file or page object file,,..
export function checkIfEleExists(ele){
return new Promise((resolve,reject)=>{
/// here if ele exists or not
cy.get('body').find( ele ).its('length').then(res=>{
if(res > 0){
//// do task that you want to perform
cy.get(ele).select('100').wait(2000);
resolve();
}else{
reject();
}
});
})
}
// here check if select[aria-label="rows per page"] exists
cy.checkIfEleExists('select[aria-label="rows per page"]')
.then(e=>{
//// now do what if that element is in ,,..
})
.catch(e=>{
////// if not exists...
})

I found a solution, hope it helps!
You can use this:
cy.window().then((win) => {
const identifiedElement = win.document.querySelector(element)
cy.log('Object value = ' + identifiedElement)
});
You can add this to your commands.js file in Cypress
Cypress.Commands.add('isElementExist', (element) => {
cy.window().then((win) => {
const identifiedElement = win.document.querySelector(element)
cy.log('Object value = ' + identifiedElement)
});
})

Cypress official document has offered a solution addressing the exact issue.
How to check Element existence
// click the button causing the new
// elements to appear
cy.get('button').click()
cy.get('body')
.then(($body) => {
// synchronously query from body
// to find which element was created
if ($body.find('input').length) {
// input was found, do something else here
return 'input'
}
// else assume it was textarea
return 'textarea'
})
.then((selector) => {
// selector is a string that represents
// the selector we could use to find it
cy.get(selector).type(`found the element by selector ${selector}`)
})

For me the following command is working for testing a VS code extension inside Code server:
Cypress.Commands.add('elementExists', (selector) => {
return cy.window().then($window => $window.document.querySelector(selector));
});
And I'm using it like this in my E2E test for a Code Server extension:
cy.visit("http://localhost:8080");
cy.wait(10000); // just an example here, better use iframe loaded & Promise.all
cy.elementExists("a[title='Yes, I trust the authors']").then((confirmBtn) => {
if(confirmBtn) {
cy.wrap(confirmBtn).click();
}
});
Just ensure that you're calling this check once everything is loaded.
If you're using Tyepscript, add the following to your global type definitions:
declare global {
namespace Cypress {
interface Chainable<Subject> {
/**
* Check if element exits
*
* #example cy.elementExists("#your-id").then($el => 'do something with the element');
*/
elementExists(element: string): Chainable<Subject>
}
}
}
Aside
VS Code server relies heavily on Iframes which can be hard to test. The following blog post will give you an idea - Testing iframes with Cypress.
The above code is needed to dismiss the "trust modal" if it's shown. Once the feature disable-workspace-trust is released it could be disabled as CLI option.

This command throws no error if element does not exist. If it does, it returns the actual element.
cypress/support/commands.js
elementExists(selector) {
cy.get('body').then(($body) => {
if ($body.find(selector).length) {
return cy.get(selector)
} else {
// Throws no error when element not found
assert.isOk('OK', 'Element does not exist.')
}
})
},
Usage:
cy.elementExists('#someSelectorId').then(($element) => {
// your code if element exists
})

In case somebody is looking for a way to use cy.contains to find an element and interact with it based on the result. See this post for more details about conditional testing.
Use case for me was that user is prompted with options, but when there are too many options, an extra click on a 'show more' button needs to be done before the 'desired option' could be clicked.
Command:
Cypress.Commands.add('clickElementWhenFound', (
content: string,
) => {
cy.contains(content)
// prevent previous line assertion from triggering
.should((_) => {})
.then(($element) => {
if (!($element || []).length) {
/** Do something when element was not found */
} else {
cy.contains(content).click();
}
});
});
Usage:
// Click button with 'Submit' text if it exists
cy.clickElementWhenFound('Submit');

Using async/await gives a clean syntax:
const $el = await cy.find("selector")
if ($el.length > 0) {
...
More info here: https://medium.com/#NicholasBoll/cypress-io-using-async-and-await-4034e9bab207

I had the same issue like button can appear in the webpage or not. I fixed it using the below code.
export function clickIfExist(element) {
cy.get('body').then((body) => {
cy.wait(5000).then(() => {
if (body.find(element).length > 0) {
cy.log('Element found, proceeding with test')
cy.get(element).click()
} else {
cy.log('Element not found, skipping test')
}
})
})
}

Get Visual Studio Code to give intellisense for custom Javascript imports

I am writing automated testing scripts using TestComplete. TestComplete mostly supports Ecmascript 2015, but it has a few quirks that are causing intellisense to not work as I would expect.
Here is two examples of code files:
File: UsefulStuffFileName.js
class UsefulStuff {
constructor(initValue) {
this.initValue = initValue;
}
get someValue(){
return this.initValue + " someValue";
}
doStuff(input) {
return input + " stuff done";
}
}
module.exports.UsefullStuff = UsefullStuff;
File: WorkingHere.js
var useful = require('UsefulStuffFileName');
class WorkingHere {
constructor() {
this.usefullStuff = new useful.UsefulStuff("Hello");
}
doCoolStuff() {
// I want intellisense options when I type the period after this.usefulStuff
// The options would be someValue, doStuff() and initValue.
// |
// |
// V
let myVariable = this.usefullStuff.someValue;
}
}
The quirks, as I see them are:
The export is done via this style: module.exports.UsefullStuff = UsefullStuff;. (This makes it work with TestComplete.)
The "import" assigns to a variable (var useful = require('UsefulStuffFileName');)
The "new"ing of the object uses the variable to access the class (new useful.UsefulStuff("Hello");).
Is there anyway to configure Visual Studio Code to understand how these files are related and give me intellisense?
Note: If I try the more standard import {UsefulStuff} from './UsefulStuffFileName'; I get an error saying "Unexpected token import" from TestComplete.

This can be done via these steps.
Change the import to look like this:
var { UsefulStuff } = require('UsefulStuff');
Change the instantiation of the class to look like this:
this.usefulStuff = new UsefulStuff("Hello");
Add a file called jsconfig.json and put this in it:
.
{
"compilerOptions": {
"baseUrl": "."
}
}

How do I require() from the console using webpack?

How do I require() / import modules from the console? For example, say I've installed the ImmutableJS npm, I'd like to be able to use functions from the module while I'm working in the console.

Here's another more generic way of doing this.
Requiring a module by ID
The current version of WebPack exposes webpackJsonp(...), which can be used to require a module by ID:
function _requireById(id) {
return webpackJsonp([], null, [id]);
}
or in TypeScript
window['_requireById'] =
(id: number): any => window['webpackJsonp'];([], null, [id]);
The ID is visible at the top of the module in the bundled file or in the footer of the original source file served via source maps.
Requiring a module by name
Requiring a module by name is much trickier, as WebPack doesn't appear to keep any reference to the module path once it has processed all the sources. But the following code seems to do the trick in lot of the cases:
/**
* Returns a promise that resolves to the result of a case-sensitive search
* for a module or one of its exports. `makeGlobal` can be set to true
* or to the name of the window property it should be saved as.
* Example usage:
* _requireByName('jQuery', '$');
* _requireByName('Observable', true)´;
*/
window['_requireByName'] =
(name: string, makeGlobal?: (string|boolean)): Promise<any> =>
getAllModules()
.then((modules) => {
let returnMember;
let module = _.find<any, any>(modules, (module) => {
if (_.isObject(module.exports) && name in module.exports) {
returnMember = true;
return true;
} else if (_.isFunction(module.exports) &&
module.exports.name === name) {
return true;
}
});
if (module) {
module = returnMember ? module.exports[name] : module.exports;
if (makeGlobal) {
const moduleName = makeGlobal === true ? name : makeGlobal as string;
window[moduleName] = module;
console.log(`Module or module export saved as 'window.${moduleName}':`,
module);
} else {
console.log(`Module or module export 'name' found:`, module);
}
return module;
}
console.warn(`Module or module export '${name}'' could not be found`);
return null;
});
// Returns promise that resolves to all installed modules
function getAllModules() {
return new Promise((resolve) => {
const id = _.uniqueId('fakeModule_');
window['webpackJsonp'](
[],
{[id]: function(module, exports, __webpack_require__) {
resolve(__webpack_require__.c);
}},
[id]
);
});
}
This is quick first shot at this, so it's all up for improvement!

Including this in a module will allow require([modules], function) to be used from a browser
window['require'] = function(modules, callback) {
var modulesToRequire = modules.forEach(function(module) {
switch(module) {
case 'immutable': return require('immutable');
case 'jquery': return require('jquery');
}
})
callback.apply(this, modulesToRequire);
}
Example Usage:
require(['jquery', 'immutable'], function($, immutable) {
// immutable and $ are defined here
});
Note: Each switch-statement option should either be something this module already requires, or provided by ProvidePlugin
Sources:
Based on this answer, which can be used to add an entire folder.
Alternative method from Webpack Docs - which allows something like require.yourModule.function()

I found a way that works, for both WebPack 1 and 2. (as long as the source is non-minified)
Repo: https://github.com/Venryx/webpack-runtime-require
Install
npm install --save webpack-runtime-require
Usage
First, require the module at least once.
import "webpack-runtime-require";
It will then add a Require() function to the window object, for use in the console, or anywhere in your code.
Then just use it, like so:
let React = Require("react");
console.log("Retrieved React.Component: " + React.Component);
It's not very pretty (it uses regexes to search the module wrapper functions) or fast (takes ~50ms the first call, and ~0ms after), but both of these are perfectly fine if it's just for hack-testing in the console.
Technique
The below is a trimmed version of the source to show how it works. (see the repo for the full/latest)
var WebpackData;
webpackJsonp([],
{123456: function(module, exports, __webpack_require__) {
WebpackData = __webpack_require__;
}},
[123456]
);
var allModulesText;
var moduleIDs = {};
function GetIDForModule(name) {
if (allModulesText == null) {
let moduleWrapperFuncs = Object.keys(WebpackData.m).map(moduleID=>WebpackData.m[moduleID]);
allModulesText = moduleWrapperFuncs.map(a=>a.toString()).join("\n\n\n");
// these are examples of before and after webpack's transformation: (which the regex below finds the var-name of)
// require("react-redux-firebase") => var _reactReduxFirebase = __webpack_require__(100);
// require("./Source/MyComponent") => var _MyComponent = __webpack_require__(200);
let regex = /var ([a-zA-Z_]+) = __webpack_require__\(([0-9]+)\)/g;
let matches = [];
let match;
while (match = regex.exec(allModulesText))
matches.push(match);
for (let [_, varName, id] of matches) {
// these are examples of before and after the below regex's transformation:
// _reactReduxFirebase => react-redux-firebase
// _MyComponent => my-component
// _MyComponent_New => my-component-new
// _JSONHelper => json-helper
let moduleName = varName
.replace(/^_/g, "") // remove starting "_"
.replace(new RegExp( // convert chars where:
"([^_])" // is preceded by a non-underscore char
+ "[A-Z]" // is a capital-letter
+ "([^A-Z_])", // is followed by a non-capital-letter, non-underscore char
"g"),
str=>str[0] + "-" + str[1] + str[2] // to: "-" + char
)
.replace(/_/g, "-") // convert all "_" to "-"
.toLowerCase(); // convert all letters to lowercase
moduleIDs[moduleName] = parseInt(id);
}
}
return moduleIDs[name];
}
function Require(name) {
let id = GetIDForModule(name);
return WebpackData.c[id].exports;
}

Being able to use require modules in the console is handy for debugging and code analysis. #psimyn's answer is very specific so you aren't likely to maintain that function with all the modules you might need.
When I need one of my own modules for this purpose, I assign a window property to it so I can get at it e.g window.mymodule = whatever_im_exporting;. I use the same trick to expose a system module if I want to play with it e.g:
myservice.js:
let $ = require('jquery');
let myService = {};
// local functions service props etc...
module.exports = myService;
// todo: remove these window prop assignments when done playing in console
window.$ = $;
window.myService = myService;
It is still a bit of a pain, but digging into the bundles, I can't see any way to conveniently map over modules.

The answer from #Rene Hamburger is good but unfortunately doesn't work anymore (at least with my webpack version). So I updated it:
function getWebpackInternals() {
return new Promise((resolve) => {
const id = 'fakeId' + Math.random();
window['webpackJsonp'].push(["web", {
[id]: function(module, __webpack_exports__, __webpack_require__) {
resolve([module, __webpack_exports__, __webpack_require__])
}
},[[id]]]);
});
}
function getModuleByExportName(moduleName) {
return getWebpackInternals().then(([_, __webpack_exports__, __webpack_require__]) => {
const modules = __webpack_require__.c;
const moduleFound = Object.values(modules).find(module => {
if (module && module.exports && module.exports[moduleName]) return true;
});
if (!moduleFound) {
console.log('couldnt find module ' + moduleName);
return;
}
return moduleFound.exports[moduleName];
})
}
getModuleByExportName('ExportedClassOfModule');

expose-loader is, in my opinion, a more elegant solution:
require("expose-loader?libraryName!./file.js");
// Exposes the exports for file.js to the global context on property "libraryName".
// In web browsers, window.libraryName is then available.

Adding the below code to one of your modules will allow you to load modules by id.
window.require = __webpack_require__;
In the console use the following:
require(34)

You could do something similar as psimyn advised by
adding following code to some module in bundle:
require.ensure([], function () {
window.require = function (module) {
return require(module);
};
});
Use require from console:
require("./app").doSomething();
See more

After making an npm module for this (see my other answer), I did a search on npms.io and seem to have found an existing webpack-plugin available for this purpose.
Repo: https://www.npmjs.com/package/webpack-expose-require-plugin
Install
npm install --save webpack-expose-require-plugin
Usage
Add the plugin to your webpack config, then use at runtime like so:
let MyComponent = require.main("./path/to/MyComponent");
console.log("Retrieved MyComponent: " + MyComponent);
See package/repo readme page for more info.
EDIT
I tried the plugin out in my own project, but couldn't get it to work; I kept getting the error: Cannot read property 'resource' of undefined. I'll leave it here in case it works for other people, though. (I'm currently using the solution mentioned above instead)

After both making my own npm package for this (see here), as well as finding an existing one (see here), I also found a way to do it in one-line just using the built-in webpack functions.
It uses WebPack "contexts": https://webpack.github.io/docs/context.html
Just add the following line to a file directly in your "Source" folder:
window.Require = require.context("./", true, /\.js$/);
Now you can use it (eg. in the console) like so:
let MyComponent = Require("./Path/To/MyComponent");
console.log("Retrieved MyComponent: " + MyComponent);
However, one important drawback of this approach, as compared to the two solutions mentioned above, is that it seems to not work for files in the node_modules folder. When the path is adjusted to "../", webpack fails to compile -- at least in my project. (perhaps because the node_modules folder is just so massive)

Codemirror- linting - Is there a event to trigger linting explictly?

I am designing an application using CodeMirror that comes with toolbar. Because of performance reason, I am not executing the lint to either through async or asynch mode.
I have provided an icon in the toolbar, on clicking this I am doing the parsing and constructing the errors. But I am stuck with how I can update lint error in editor?
Any pointer would be really helpful.

The lint addon adds an "extension" method to all Editor instances called performLint, combine with editor options of lint: { lintOnChange: false }, and then you can invoke the linter by calling mirror.performLint().
If you define your own lint methods ala
CodeMirror.registerHelper('lint', 'mode', (text) => { /* your cool stuff here */ })
that'll get invoked on performLint().

Have you tried setting the lint value dynamically using the below code?
//enable
editor.setOption("lint",true);
//disable
editor.setOption("lint",false);
You can see a demo here JSFiddle link

To trigger lint in one line:
// trigger registered lint handler
editor.setOption("lint", {});
// trigger custom lint handler defined on the fly
editor.setOption("lint", {
getAnnotations: function() { /* some smart code */ return found; }
});
If you wonder why it should ever work, have look into addon/lint/lint.js, specially the following lines:
CodeMirror.defineOption("lint", false, function(cm, val, old) {
...
if (val) {
...
startLinting(cm);
}
});

It sounds like a good feature that doesn't appear to exist.
It is straighforward to create a button to launch a validation from an external button.
For example [no credit] https://jsfiddle.net/q43drhyk/
function checkFormat(editor) {
var success = JSHINT(editor.getValue());
var output = '';
if (!success) {
output = "Check format error:\n\n";
for (var i in JSHINT.errors) {
var err = JSHINT.errors[i];
if (null != err) {
output += err.line + '[' + err.character + ']: ' + err.reason + '\n';
} else {
output += "Check format unknown error:\n";
}
}
alert(output);
}
return success;
}
However this does not render the validation messages in the CodeMirror editor to display in the linenumber gutter, which is what the OP was looking for.
To do that, you could customise the lint add-on code.
For example from the json-lint provided in the standard addons
[https://github.com/codemirror/CodeMirror/blob/master/addon/lint/json-lint.js]
1.Extract the body of registerHelper() into a new function that reproduces the existing function:
CodeMirror.registerHelper("lint", "json", function(text) {
return mylinthandler(text)
}
mylinthandler(text) {
var found = [];
jsonlint.parseError = function(str, hash) {
var loc = hash.loc;
found.push({from: CodeMirror.Pos(loc.first_line - 1, loc.first_column),
to: CodeMirror.Pos(loc.last_line - 1, loc.last_column),
message: str});
};
try { jsonlint.parse(text); }
catch(e) {}
return found;
}
Turn off the auto-lint CodeMirror options with.
lintOnChange: false
Then when you wish to lint, call
mylinthandler(editor.getValue())

Hot Code Push NodeJS

I've been trying to figure out this "Hot Code Push" on Node.js. Basically, my main file (that is run when you type node app.js) consists of some settings, configurations, and initializations. In that file I have a file watcher, using chokidar. When I file has been added, I simply require the file. If a file has been changed or updated I would delete the cache delete require.cache[path] and then re-require it. All these modules don't export anything, it just works with the single global Storm object.
Storm.watch = function() {
var chokidar, directories, self = this;
chokidar = require('chokidar');
directories = ['server/', 'app/server', 'app/server/config', 'public'];
clientPath = new RegExp(_.regexpEscape(path.join('app', 'client')));
watcher = chokidar.watch(directories, {
ignored: function(_path) {
if (_path.match(/\./)) {
!_path.match(/\.(js|coffee|iced|styl)$/);
} else {
!_path.match(/(app|config|public)/);
}
},
persistent: true
});
watcher.on('add', function(_path){
self.fileCreated(path.resolve(Storm.root, _path));
//Storm.logger.log(Storm.cliColor.green("File Added: ", _path));
//_console.info("File Updated");
console.log(Storm.css.compile(' {name}: {file}', "" +
"name" +
"{" +
"color: white;" +
"font-weight:bold;" +
"}" +
"hr {" +
"background: grey" +
"}")({name: "File Added", file: _path.replace(Storm.root, ""), hr: "=================================================="}));
});
watcher.on('change', function(_path){
_path = path.resolve(Storm.root, _path);
if (fs.existsSync(_path)) {
if (_path.match(/\.styl$/)) {
self.clientFileUpdated(_path);
} else {
self.fileUpdated(_path);
}
} else {
self.fileDeleted(_path);
}
//Storm.logger.log(Storm.cliColor.green("File Changed: ", _path));
console.log(Storm.css.compile(' {name}: {file}', "" +
"name" +
"{" +
"color: yellow;" +
"font-weight:bold;" +
"}" +
"hr {" +
"background: grey" +
"}")({name: "File Changed", file: _path.replace(Storm.root, ""), hr: "=================================================="}));
});
watcher.on('unlink', function(_path){
self.fileDeleted(path.resolve(Storm.root, _path));
//Storm.logger.log(Storm.cliColor.green("File Deleted: ", _path));
console.log(Storm.css.compile(' {name}: {file}', "" +
"name" +
"{" +
"color: red;" +
"font-weight:bold;" +
"}" +
"hr {" +
"background: grey" +
"}")({name: "File Deleted", file: _path.replace(Storm.root, ""), hr: "=================================================="}));
});
watcher.on('error', function(error){
console.log(error);
});
};
Storm.watch.prototype.fileCreated = function(_path) {
if (_path.match('views')) {
return;
}
try {
require.resolve(_path);
} catch (error) {
require(_path);
}
};
Storm.watch.prototype.fileDeleted = function(_path) {
delete require.cache[require.resolve(_path)];
};
Storm.watch.prototype.fileUpdated = function(_path) {
var self = this;
pattern = function(string) {
return new RegExp(_.regexpEscape(string));
};
if (_path.match(pattern(path.join('app', 'templates')))) {
Storm.View.cache = {};
} else if (_path.match(pattern(path.join('app', 'helpers')))) {
self.reloadPath(path, function(){
self.reloadPaths(path.join(Storm.root, 'app', 'controllers'));
});
} else if (_path.match(pattern(path.join('config', 'assets.coffee')))) {
self.reloadPath(_path, function(error, config) {
//Storm.config.assets = config || {};
});
} else if (_path.match(/app\/server\/(models|controllers)\/.+\.(?:coffee|js|iced)/)) {
var isController, directory, klassName, klass;
self.reloadPath(_path, function(error, config) {
if (error) {
throw new Error(error);
}
});
Storm.serverRefresh();
isController = RegExp.$1 == 'controllers';
directory = 'app/' + RegExp.$1;
klassName = _path.split('/');
klassName = klassName[klassName.length - 1];
klassName = klassName.split('.');
klassName.pop();
klassName = klassName.join('.');
klassName = _.camelize(klassName);
if (!klass) {
require(_path);
} else {
console.log(_path);
self.reloadPath(_path)
}
} else if (_path.match(/config\/routes\.(?:coffee|js|iced)/)) {
self.reloadPath(_path);
} else {
this.reloadPath(_path);
}
};
Storm.watch.prototype.reloadPath = function(_path, cb) {
_path = require.resolve(path.resolve(Storm.root, path.relative(Storm.root, _path)));
delete require.cache[_path];
delete require.cache[path.resolve(path.join(Storm.root, "server", "application", "server.js"))];
//console.log(require.cache[path.resolve(path.join(Storm.root, "server", "application", "server.js"))]);
require("./server.js");
Storm.App.use(Storm.router);
process.nextTick(function(){
Storm.serverRefresh();
var result = require(_path);
if (cb) {
cb(null, result);
}
});
};
Storm.watch.prototype.reloadPaths = function(directory, cb) {
};
Some of the code is incomplete / not used as I'm trying a lot of different methods.
What's Working:
For code like the following:
function run() {
console.log(123);
}
Works perfectly. But any asynchronous code fails to update.
Problem = Asynchronous Code
app.get('/', function(req, res){
// code here..
});
If I then update the file when the nodejs process is running, nothing happens, though it goes through the file watcher and the cache is deleted, then re-established. Another instance where it doesn't work is:
// middleware.js
function hello(req, res, next) {
// code here...
}
// another file:
app.use(hello);
As app.use would still be using the old version of that method.
Question:
How could I fix the problem? Is there something I'm missing?
Please don't throw suggestions to use 3rd party modules like forever. I'm trying to incorporate the functionality within the single instance.
EDIT:
After studying meteors codebase (there's surprisingly little resources on "Hot Code Push" in node.js or browser.) and tinkering around with my own implementation I've successfully made a working solution. https://github.com/TheHydroImpulse/Refresh.js . This is still at an early stage of development, but it seems solid right now. I'll be implementing a browser solution too, just for sake of completion.

Deleting require's cache doesn't actually "unload" your old code, nor does it undo what that code did.
Take for example the following function:
var callbacks=[];
registerCallback = function(cb) {
callbacks.push(cb);
};
Now let's say you have a module that calls that global function.
registerCallback(function() { console.log('foo'); });
After your app starts up, callbacks will have one item. Now we'll modify the module.
registerCallback(function() { console.log('bar'); });
Your 'hot patching' code runs, deletes the require.cached version and re-loads the module.
What you must realize is that now callbacks has two items. First, it has a reference to the function that logs foo (which was added on app startup) and a reference to the function that logs bar (which was just added).
Even though you deleted the cached reference to the module's exports, you can't actually delete the module. As far as the JavaScript runtime is concerned, you simply removed one reference out of many. Any other part of your application can still be hanging on to a reference to something in the old module.
This is exactly what is happening with your HTTP app. When the app first starts up, your modules attach anonymous callbacks to routes. When you modify those modules, they attach a new callback to the same routes; the old callbacks are not deleted. I'm guessing that you're using Express, and it calls route handlers in the order they were added. Thus, the new callback never gets a chance to run.
To be honest, I wouldn't use this approach to reloading you app on modification. Most people write app initialization code under the assumption of a clean environment; you're violating that assumption by running initialization code in a dirty environment – that is, one which is already up and running.
Trying to clean up the environment to allow your initialization code to run is almost certainly more trouble than it's worth. I'd simply restart the entire app when your underlying files have changed.

Meteor solves this problem by allowing modules to "register" themselves as part of the hot code push process.
They implement this in their reload package:
https://github.com/meteor/meteor/blob/master/packages/reload/reload.js#L105-L109
I've seen that Meteor.reload API used in some plugins on GitHub, but they also use it in the session package:
https://github.com/meteor/meteor/blob/master/packages/session/session.js#L103-L115
if (Meteor._reload) {
Meteor._reload.onMigrate('session', function () {
return [true, {keys: Session.keys}];
});
(function () {
var migrationData = Meteor._reload.migrationData('session');
if (migrationData && migrationData.keys) {
Session.keys = migrationData.keys;
}
})();
}
So basically, when the page/window loads, meteor runs a "migration", and it's up to the package to define the data/methods/etc. that get recomputed when a hot code push is made.
It's also being used by their livedata package (search reload).
Between refreshes they're saving the "state" using window.sessionStorage.