There’s frequently some confusion about the differences between Processing, Processing.js, and p5.js. All three aim to run the same code, so projects created in one should translate well to the others. However, there are important differences.
Khan Academy hired John Resig, and (among other things) had him work on their Live Editor. KA PJS programs use Processing.js. Processing.js has not been actively maintained, and as of yesterday (December 4, 2018) has been archived. So there will be no changes to Processing.js in the future. New programs, for example, on OurJSEditor, should use p5.js, the maintained and official version. It remains to be seen if KA will ever switch away from Processing.js or if they will even maintain their own fork.