NPM provides a command to check for outdated packages:
$ npm help outdated
However, by default, the command checks the entire dependency tree, not only the modules specified in package.json, but also the dependencies of those modules. If we only care about the top-level packages, we can add --depth option to show just that:
$ npm outdated --depth 0
This is similar to listing installed packages:
$ npm list --depth 0
Using the option, it will not print out the nested dependency tree, but only the top-level. The option is similar to tree -L 1, but zero indexed instead of one.
Another interesting thing about outdated command is the color coding in the output: