Getting the following error when trying to install anything with npm - terminal

Question

Whenever I try to install packages I get this error:
/usr/local/bin/karma -> /usr/local/lib/node_modules/karma/bin/karma
npm ERR! Darwin 14.5.0
npm ERR! argv "node" "/usr/local/bin/npm" "install" "-g" "karma"
npm ERR! node v0.12.7
npm ERR! npm v2.11.3
npm ERR! code EPEERINVALID
npm ERR! peerinvalid The package karma does not satisfy its siblings' peerDependencies requirements!
npm ERR! peerinvalid Peer grunt-karma#0.6.2 wants karma#~0.10.0
npm ERR! peerinvalid Peer karma-html2js-preprocessor#0.1.0 wants karma#>=0.9
npm ERR! peerinvalid Peer karma-mocha#0.1.10 wants karma#>=0.12.8
npm ERR! peerinvalid Peer karma-phantomjs-launcher#0.1.4 wants karma#>=0.9
npm ERR! peerinvalid Peer karma-script-launcher#0.1.0 wants karma#>=0.9
npm ERR! peerinvalid Peer karma-jasmine#0.1.6 wants karma#>=0.9
npm ERR! peerinvalid Peer karma-requirejs#0.2.2 wants karma#>=0.9
npm ERR! peerinvalid Peer karma-coffee-preprocessor#0.1.3 wants karma#>=0.9
npm ERR! Please include the following file with any support request:
npm ERR! /Applications/Xcode-beta.app/Contents/Developer/npm-debug.log
I've tried uninstalling/reinstalling npm, node and karma but to no avail
also tried:
rm -rf /usr/local/lib/node_modles/karma-*
npm cache clean -g

Answer 1

I had the same error for generator-karma and here's what I did:
Run this:
[sudo] npm -g ls --depth=0
It'll show you the list of modules, like this:
├── bower#1.5.2
├── david#6.2.0
├── express#4.13.3
├── express-generator#4.13.1
├── generator-karma#1.0.0 peer invalid
├── grunt#0.4.5
├── grunt-cli#0.1.13
├── gulp#3.9.0
├── ionic#1.6.4
├── jscs#2.1.1
├── jshint#2.8.0
├── less#2.5.1
├── mean-cli#0.10.14
├── mocha#2.3.0
├── node-inspector#0.12.3
├── nodemon#1.4.1
├── nodesql#0.2.4
├── npm#2.11.3
├── pm2#0.14.7
├── sass#0.5.0
├── sqlite3#3.0.10
├── todo#1.1.0
└── yo#1.4.7
See this line: generator-karma#1.0.0 peer invalid ?
This is the problematic one, you should see something similar in your output. You can either try to update it with [sudo] npm -g update generator-karma or remove it with [sudo] npm -g uninstall generator-karma and do what you wanted to do in the first place.
After that, re-installing it again or leaving it like this is up to you.