Depends what you mean by "library ecosystem". If it's raw number of packages then npm is number one. On direct opposite side of spectrum you can find e.g. Elixir/Phoenix - relatively small number of packages in registry but even built-in stuff covers 99% of what you want - and makes this effortless for you. E.g. after single `mix phx.new YourAppName` You get

* Pre-confugured prod/dev/test environments

* Preconfigured webpack for the environments above

* DB migrations

* telemetry/metrics with live dashboard

etc

P.S. encrypted signed cookies, changesets (validations for db models or arbitrary forms), clustering, websocket stuff, "liveview" serverside rendering ...