npm run dev not working

[saadsaeed01]

i have Ubuntu 16.04 installed and i am trying to run npm run dev but ts not working. This is the log file
npm-debug.log.

[saadsaeed01]

This is the error

@ dev /var/www/html/my_laravel
npm run development

@ development /var/www/html/my_laravel
cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js

/var/www/html/my_laravel/node_modules/laravel-mix/setup/webpack.config.js:24
let WebpackConfig = require('../src/builder/WebpackConfig');
^^^

SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
at exports.runInThisContext (vm.js:53:16)
at Module._compile (module.js:374:25)
at Object.Module._extensions..js (module.js:417:10)
at Module.load (module.js:344:32)
at Function.Module._load (module.js:301:12)
at Module.require (module.js:354:17)
at require (internal/module.js:12:17)
at requireConfig (/var/www/html/my_laravel/node_modules/webpack/bin/convert-argv.js:97:18)
at /var/www/html/my_laravel/node_modules/webpack/bin/convert-argv.js:104:17
at Array.forEach (native)

npm ERR! Linux 4.10.0-37-generic
npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "run" "development"
npm ERR! node v4.2.6
npm ERR! npm v3.5.2
npm ERR! code ELIFECYCLE
npm ERR! @ development: cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the @ development script 'cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! /var/www/html/my_laravel/npm-debug.log

npm ERR! Linux 4.10.0-37-generic
npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "run" "dev"
npm ERR! node v4.2.6
npm ERR! npm v3.5.2
npm ERR! code ELIFECYCLE
npm ERR! @ dev: npm run development
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the @ dev script 'npm run development'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! npm run development
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! /var/www/html/my_laravel/npm-debug.log