Rulers Guides.js
Creates Photoshop-like guides and rulers interface on a web page
Blaver
A JavaScript library built on top of the Faker.JS library. It generates massive amounts of fake data in the browser and node.js.
Spa Eye
Backbone debugger for Firefox
Csscomb.js
CSS coding style formatter
Should.js
BDD style assertions for node.js -- test framework agnostic
Qunit
An easy-to-use JavaScript Unit Testing framework.
Casper JS
Navigation scripting & testing utility for PhantomJS and SlimerJS
Pioneer
Integration Testing
Jasmine
DOM-less simple JavaScript testing framework
Jasmine Ajax
jasmine-ajax - A library for faking Ajax responses in your Jasmine suite.
Angular Debaser
Just a better way to test AngularJS apps.
Js Cover
JSCover is a tool that measures code coverage for JavaScript programs.
Bower
A package manager for the web, created at Twitter
Trace Kit
Attempts to create stack traces for unhandled JavaScript exceptions in all major browsers.
Gulp
The streaming build system
Fast Check
Property based testing framework for JavaScript (like QuickCheck) written in TypeScript
Stacktrace.js
Framework-agnostic, micro-library for getting stack traces in all web browsers