Scripting in the 3rd Party True Tales of Horror and Hope

In a dystopian cyberpunk future, website features are added by the simple addition of a snippet of javascript. These scripts, never before run or tested together, interact, and birth an artificial intelligence bent on taking vengeance on the people responsible for its creation. Or the styles look funky, and there’s a name collision on a cookie or something. Writing scripts for someone else’s page presents unique challenges, from a hostile global namespace, to unintended module system interactions, to load order race conditions, to mysteriously broken implementations of JSON.stringify(). In this talk we will go about learning how to diagnose, remedy and defend against problems like these. Further, we’ll go over patterns for reliably writing, building, testing and delivering scripts into hostile or unexplored environments, based on my own experiences of dread, regret, elation and hope, delivering code into millions of other people’s page views, daily.