When you say everything contained in the project, you forget that there's more to life than just node/javascript. Just two silly examples: you cannot run/deploy your API backend without docker/kubernetes/aws-cli/etc, nor your mobile app even if it's in JavaScript (react-native).
The only way to keep to node/javascript is if you only develop libraries (a website that doesn't get deployed -> still on library level).
The only way to keep to node/javascript is if you only develop libraries (a website that doesn't get deployed -> still on library level).