To check if any module in a project is ‘old’:
npm outdated
‘outdated’ will check every module defined in package.json and see if there is a newer version in the NPM registry.
For example, say xml2js 0.2.6 (located in node_modules in the current project) is outdated because a newer version exists (0.2.7). You would see:
xml2js@0.2.7 node_modules/xml2js current=0.2.6
To update all dependencies, if you are confident this is desirable:
npm update
Or, to update a single dependency such as xml2js:
npm update xml2js
To update package.json version numbers, append the --save flag:
npm update --save