It's probably worth pointing out that Slack _also_ contains a ton of native code, written in C++ (with a bit of C++/CX and Objective-C). All of us on our small team have an extensive background in typed languages, including giant code bases (Windows, for example).
We just also happen to really like JavaScript, feeling that it and the ecosystem around us makes us more productive given our needs. TypeScript a few years ago was simply not good enough, and neither were the alternatives.
It's okay if you feel otherwise, but trust that there are quite a few developers out there who are comfortable with building and maintaining rather large JavaScript codebases, building pretty impressive applications with it. This post isn't yet another "JavaScript is terrible" rant, I quite like it.
We just also happen to really like JavaScript, feeling that it and the ecosystem around us makes us more productive given our needs. TypeScript a few years ago was simply not good enough, and neither were the alternatives.
It's okay if you feel otherwise, but trust that there are quite a few developers out there who are comfortable with building and maintaining rather large JavaScript codebases, building pretty impressive applications with it. This post isn't yet another "JavaScript is terrible" rant, I quite like it.