Laravel: compile node_modules to app.js and app.css - node-modules

Question

I've created a new Laravel-project using composer
./composer.phar create-project laravel/laravel --prefer-dist ProjectName
Next, I've added the required packages through npm. I've already noticed the --save switch is necessary to make it work correctly:
npm install jquery --save
npm install bootstrap --save
npm install font-awesome --save
When I show the packages in this directory:
npm list --depth=0
# /var/www/ProjectName
├── axios#0.16.2
├── bootstrap#3.3.7
├── bootstrap-sass#3.3.7
├── cross-env#5.0.5
├── font-awesome#4.7.0
├── jquery#3.2.1
├── laravel-mix#1.4.5
├── lodash#4.17.4
└── vue#2.4.4
Nothing is listed as extraneous.
Now, I'm trying to compile these assets (js and css) into 2 files, which are easy to include in the blade-template.
The docs say I have to use npm run dev, but this fails with the most cryptic message you can ever imagine.
events.js:141
throw er; // Unhandled 'error' event
^
Extras
Call stack:
Error: spawn node_modules/webpack/bin/webpack.js ENOENT
at exports._errnoException (util.js:907:11)
at Process.ChildProcess._handle.onexit (internal/child_process.js:189:32)
at onErrorNT (internal/child_process.js:363:16)
at nextTickCallbackWith2Args (node.js:511:9)
at process._tickCallback (node.js:425:17)
at Function.Module.runMain (module.js:443:11)
at startup (node.js:140:18)
at node.js:1043:3
The npm run dev command results in following command:
cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js
Versions:
npm ERR! node -v v4.8.2
npm ERR! npm -v 1.4.21
I've put the entire output online as well:
output
Why isn't it possible to compile the assets? How can I fix this?
EDIT:
All right found it!
somehow i reinstalled nodejs to not have the legacy-version.
These are the commmands I ran:
sudo apt-get remove nodejs
curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
sudo apt-get -y install nodejs
sudo apt-get install dh-autoreconf
rm -rf node_modules
rm package-lock.json yarn.lock
npm cache clear --force
npm install
npm install bootstrap --save
npm list --depth=0
npm run dev

Answer 1

Try removing the contents of node_modules/
rm -Rfv your_project_path/node_modules/
then
npm install
Let me know if it helps.