Update all npm packages in multiple projects in subfolders

First run a read-only pass so you can see which projects would change:

#!/usr/bin/env bash

for dir in */; do
  if [ -f "${dir}package.json" ]; then
    echo "Checking $dir"
    (
      cd "$dir" || exit
      npx --yes npm-check-updates
    )
  fi
done

When you are ready to update a project, run this inside that project:

npx npm-check-updates -u
npm install
npm test

npm-check-updates -u changes the version ranges in package.json. npm install then updates the lockfile and installed dependencies.

Do not delete every node_modules directory as part of the loop. It adds work and makes it harder to test projects one at a time. Major dependency updates can contain breaking changes, so use a clean Git working tree, review each diff, and run that project’s own tests and build before moving to the next folder.