karma start throwing useragent error - node.js

Question

I generated an app using yeoman by doing this in a folder called sw-front:
yo angular
I installed karma like this
npm install -g karma
npm install -g karma-cli
grunt serve works fine.
karma -v throws the same error:
mm-mac-2186:sw-front pkatepalli$ karma start
module.js:340
throw err;
^
Error: Cannot find module 'useragent'
at Function.Module._resolveFilename (module.js:338:15)
at Function.Module._load (module.js:280:25)
at Module.require (module.js:364:17)
at require (module.js:380:17)
at Object.<anonymous> (/Users/pkatepalli/Desktop/hands-on-angular/sw-front/node_modules/karma/lib/helper.js:4:17)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Module.require (module.js:364:17)
module.js:
var Module = function() {
var providers = [];
this.factory = function(name, factory) {
providers.push([name, 'factory', factory]);
return this;
};
this.value = function(name, value) {
providers.push([name, 'value', value]);
return this;
};
this.type = function(name, type) {
providers.push([name, 'type', type]);
return this;
};
this.forEach = function(iterator) {
providers.forEach(iterator);
};
};
module.exports = Module;
mm-mac-2186:sw-front pkatepalli$ node -v
v0.10.28
mm-mac-2186:sw-front pkatepalli$ npm -v
1.4.9

Answer 1

Try
npm cache clean
And removing the node_modules directory, if it exists, where you are running the commands form.
Then rebuild/reinstall