Angular JS module issue with MEAN stack

Any one please. Any idea whats i am doing wrong, i am trying all possible solution still having issue while running the server.

Training/register_login/server $ node server
module.js:472
throw err;
^
Error: Cannot find module 'cors'
at Function.Module._resolveFilename (module.js:470:15)
at Function.Module._load (module.js:418:25)
at Module.require (module.js:498:17)
at require (internal/module.js:20:19)
at Object.<anonymous> (Training/register_login/server/server.js:4:12)
at Module._compile (module.js:571:32)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)

via sajid ali