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A port of the Processing visualization language to JavaScript.

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This is the compilation repository for Processing.js, building the processing.js library from a series of modules, rather than existing as one large file as was the case in version 1.4.1 and earlier.

Clone the usual way, ensure you have node.js installed ( and install the require node packages by typing npm install in the processing-js directory. Then it's a fairly straight forward process:

  1. Lint: $> grunt
  2. Test: $> node test

If step 1 gives you a "grunt: command not found" or similar error, run npm install -g grunt-cli to make sure grunt is globally installed as CLI command.

The test script accepts the following arguments:

  • --test=testfile.pde runs one specific test
  • --nobuild does not build Pjs if all tests pass
  • --failonerror terminates the run if any error occurs.
  • --noref will not start a server process and a browser for doing ref testing.
  • --noautoref will start a server and a browser for ref testing, but doesn't auto-start the tests.

You can also perform the post-unit-test steps manually:

  • Build processing.js: $> browserify build.js -o processing.js
  • Minify processing.js: $> node minify
  • Run test server: $> node server

In the browser

With the test server running, the following urls are good to know:


A port of the Processing visualization language to JavaScript.





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  • Processing 97.2%
  • JavaScript 2.8%