Problem: While running gulp on laravel following error is displayed:

Error: Cannot find module 'laravel-elixir-group'
    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. (/var/www/netsend-mobile/clientportal/gulpfile.js:2:19)
    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)

Solution:

1. Update Gulpfile.js

var elixir = require('laravel-elixir');
var ElixirGroup = require('laravel-elixir-group');

2. Add laravel-elixir-group into the package.json

{
  "private": true,
  "devDependencies": {
    "gulp": "^3.8.8",
    "laravel-elixir-group": "0.0.5"
  },
  "dependencies": {
    "laravel-elixir": "^4.0.0",
    "bootstrap-sass": "^3.0.0"
  }
}

3. Run npm install

npm install

4. After this you can run gulp.

Thanks