You must install peer dependencies yourself

Question

sudo npm install

result:

npm WARN [email protected] requires a peer of sinon@>=2.1.0 <5 but none is installed. You must install peer dependencies yourself.

Answer 1

npm does not install dependencies specified as peerDependecy. This may seem unpleasing for people who used to bower, but that's no problem. You'll get used to it soon.

peerDependencies are dependencies that the package developer actually depends on it, but doesn't mention it as dependency. He/She/They (the developers) just suppose that wherever their package is going to be used, there will be karma-sinon-chai.

You need to install peerDependencys of a package yourself!