Why does npm insist about "UNMET PEER DEPENDENCY"?

Question

I searched and read many posts about "npm UNMET PEER DEPENDENCY" issues. But this one is still confusing:

Hulk node_modules # npm install -g rxjs@5.0.0-beta.6
- symbol-observable@0.2.4 node_modules/rxjs/node_modules/symbol-observable
/usr/lib
└── rxjs@5.0.0-beta.6

Hulk node_modules # npm install -g zone.js@^0.6.6
/usr/lib
└── zone.js@0.6.12

Hulk node_modules #
Hulk node_modules #
Hulk node_modules #
Hulk node_modules #
Hulk node_modules # npm install -g @angular/core
/usr/lib
├── @angular/core@2.0.0-rc.1
├── UNMET PEER DEPENDENCY rxjs@5.0.0-beta.6
└── UNMET PEER DEPENDENCY zone.js@^0.6.6

npm WARN @angular/core@2.0.0-rc.1 requires a peer of rxjs@5.0.0-beta.6 but none was installed.
npm WARN @angular/core@2.0.0-rc.1 requires a peer of zone.js@^0.6.6 but none was installed.

First when I try to install "@angular/core", npm complained about dependencies.

I installed those dependencies, it still complains.

Why? Thanks for your insights.

Answer 1

Try:

In unix terminal:

• remove your node modules:

  $ rm -rf node_modules

• clear cache:

  $ npm cache clean

• reinstall (assuming your package.json is correct):

  $ npm install