digging into the code for the p5js web editor Seems it uses jshint for doing its static code analysis, and currently there’s an issue already open for supporting async/await here! 
, so I gave that issue a thumbs up at least! https://github.com/jshint/jshint/issues/2604
also just to note this down somewhere (not really important to this issue / thread I guess), it seems that it uses codemirror https://codemirror.net/, and there seems to be a lot of unused potential there (stuff I would want enabled!) in the addons section for it https://codemirror.net/doc/manual.html#addons. eg. the match-highlighter.js! (highlighting the selected variable other places in code), and also tern/tern.js for multiple occurrence matching & refactoring. But I guess at some point it would just make more sense to switch to your IDE of choice, where you have all the features you find comfortable! 