It's hard to argue that the all-round experience JavaScript development is better than say Java/C#. The former language has to deal with at least 2 different ec

It's hard to argue that the all-round experience JavaScript development is better than say Java/C#. The former language has to deal with at least 2 different ecosystems: NodeJS and Browser and the latter usually try its best to give consistent experience everywhere. One would argue that optimizing for specific environment is better but in the case of JavaScript, I don't feel that way. The library/tools churn in JavaScript is another issue that a few people have raised as a concern. I used to think that companies are crazy (or wasteful) to create their own collection/mvc/widget/utility libraries or tools but I suppose it's better than to migrate from one used-to-be-popular library to another current-du-jour library by the time your infrastructure (build, test, packaging pipeline) is already set in stone and you're focusing on building products. JavaScript for large app/large team, does it work? yes it does. But you have to be _very_ discipline and skilled. Apprenticeship might work for C#/C++/Java/Rails (yes, Rails specifically) but it's definitely harder in JavaScript. Some people might not like to hear this but for a large team/large app, you have to impose structure, convention, rules, etc which may be at odds with the liberty/freedom that JavaScript can offer. Those DO's items for JavaScript such as to build small contained function/libraries may not applied as-is given certain complex requirements (say Single Page App). Eventually your controller/presenter code evolve (sure, we still try our best to break down the complexity but it won't be as cute as underscore library). Disclaimer: I use JavaScript every day and am part of the team that builds large products (SAP Lumira, SAP Cloud for Analytics) using JavaScript (90-95% of the code base, front-end and back-end. Yes, that's right ;) SAP+JavaScript).