In the recent weeks, multiple have requested support for the following two NPM replacements:

• yarn, which has a lot of speed improvements. Many users reported problems using yarn with the CLI in some occasions.
• cnpm, which uses an NPM cache specially made for China. It's not useful for anyone outside of China itself.

What I suggest is embracing the fact that users can have an angular-cli.json file in their home folder to specify which NPM replacement they want to use.

Something like adding to the configuration:

{ // ...
  "packageManager": "npm"  // or "cnpm" or "yarn"
}

And having special code for some of them when the user creates a new package.

I think this is the cleanest way to do it. If we document it well, users won't have a problem. They can even replace its value per-project.

cc @IgorMinar