Is there a simple way to reinstall all packages that my app depends on (i.e. they are in my apps node_modules folder)?
Follow this step to re install node modules and update them
works even if node_modules folder does not exist. now execute the following command synchronously. you can also use "npm update" but I think this'd preferred way
npm outdated // not necessary to run this command, but this will show outdated dependencies
npm install -g npm-check-updates // to install the "ncu" package
ncu -u --packageFile=package.json // to update dependencies version in package.json...don't run this command if you don't need to update the version
npm install: will install dependencies in your package.json file.
if you're okay with the version of your dependencies in your package.json file, no need to follow those steps just run
npm install