Front-End Developer Handbook
"A whole lot of developers adopt static type checking for mostly subjective reasons or band wagon emotions.  Some sell out completely to Typescript and the Microsoft way of doing things while others take on a slower approach with Flow. One thing is for sure, most developers don't need types, they are simply complicating already complex problems and solutions. Like most things, most of this trend is subjective dogma not objective value."<p>Wow, biased much.  I love JavaScript and ES6.  But anything that I work with a team on or expect to live beyond a month or so, I love types for.  Making a large refactor without types is the wild west. Types help provide structure/understanding about the data flowing through your system.  And if you need to eject you can with Any. I used to prefer pure JS (or Python), certainly quicker to prototype, but also more difficult to grow and maintain.  Tradeoffs in both directions.  Such an amateur statement makes me question the rest of the document.