npm update does not do anything

The npm update --dd output says why at the end:

...not updating @angular/common because it's currently at the maximum version that matches its specified semver range

Look at this specific package, angular/common. You have it set to 2.0.0, which means npm will always fetch that specific version. If you want the package to update, you need to use a semver range. You can view a comprehensive list of semver ranges here, but the most commonly used are probably ~ and ^.

~ means that the patch version will update. So if you have version ~1.2.1, it will update to any 1.2.x, but never to 1.3.0.

^ updates the minor version, so if you have ^1.2.1, it will update to any 1.x.x release, but never to 2.0.0.

To update, here are the steps:

1. Running npm outdated will allow you to check all the packages that need to be updated. The list will show current, wanted and latest version of each package.

2. Next, run npm update which will update all the packages to the latest possible version as defined in package.json. For example, if a certain package in package.json has version ^2.3.1 then this package will not be updated beyond 2.x.x, and if a package has version ~5.3.2 then it will not be updated beyond 5.3.x. (to understand semantic versioning, read this)

3. But what if you want to update to the latest, and the versions of your packages in package.json are preventing you from updating as described in step 2 above? Well there are two solutions.

   a) You can manually update the package versions in package.json by changing the versions of your packages to the latest values you like them to be. Although this might work, this is very tedious and error prone. So I do not recommend it.

   b) You can automatically update the versions of your packages in package.json. To do so, you need to install the npm-check-updates package (I typically install this package globally) using this command: npm i -g npm-check-updates. Once this is done, you have to run ncu -u. This will only update the package versions in package.json to the latest version. I recommend this method.

4. Now, after updating the versions of your packages in package.json, run npm update and your packages will be updated to the latest version.

If npm [-g] outdated shows outdated packages outside of the semver range (e.g. a major update), the update command cannot be used to update these packages.

To install the latest version, explicitly specify the package with

npm install [-g] <package>