An app for making visual comparisons
JavaScript CSS HTML Shell


An app for making visual comparisons.

Negative Usage

Follow @NegativeJS on Twitter for important updates.


Important Note: Users running Negative v0.10.0 may experience an application crash when opening the Settings window. Negative v0.10.1 solves this issue. If the update did not download automatically, please download it manually from the link below. If automatic updates were enabled, it is very likely that v0.10.1 was automatically installed after the crash. Please check your version in "Negative > About Negative". If the version is v0.10.1 or higher, no further action is needed on your part. I apologize for any inconvenience this may have caused you. - Adam

User Documentation

Please check negative/releases for details on changes between versions.


All contributions are welcome!! Please check negative/issues for things that need attention, or feel free to create your own. Please make sure you create an issue first, and then do the work and a submit a PR.


Currently only Mac OS X is supported.

  1. Install Node.js >= v6
  2. git clone
  3. cd negative
  4. npm install
  5. npm run build
  6. Locate and copy dist/Negative-darwin-x64/ to your Applications folder


Important: Tests get run against the built app. If you are attempting to run tests and the results are not what you expected, you need to npm run build again.

  1. npm run build
  2. npm test



  • gulp - Compile, combine, and minify files for the renderer process. This isn't necessary for files in the main process. Make sure this is running when working on UI.

NPM Scripts

  • npm start - Start the app with the following environment variables:
    • NODE_ENV=development
  • npm run build - Build the production app
    1. Compiles JavaScript and Sass
    2. Copies necessary files to ./release/
    3. Runs npm install --production in ./release/
    4. Builds the app moves it to ./dist/
  • npm run lint - Run ESLint
  • npm test - Run Mocha tests
  • npm run travis
    1. Run build
    2. Run test
  • npm run open - Starts the app from dist/Negative-darwin-x64/
  • npm run dmg
    1. Run build
    2. Move dist/Negative-darwin-x64/ to dist/release/
    3. Create dist/release/Negative.dmg


Created by Adam Drago. Built on Electron.