I was part of the team that built an editorial admin panel for the most read news site in my country. The initial development phase ended around three years ago and it's been in a sort of continuous development mode since then. A whole bunch of people have added features to the codebase (and upgraded it from 0.16 to 0.17 and 0.18) after me and the other original devs left.

It is still going strong and is so reliable that there's no need for dedicated developer for that project. I honestly can't imagine any sort of JavaScript project could have survived through the years that well.