AngularJS ES6 Webpack – couldn’t process source due to parse error,’import’ and ‘export’ may appear only with ‘sourceType: module’

I am trying to compile a project written with AngularJS ES6 and when compiling it throws me the following error

ERROR in ./src/app.module.js
Module build failed: error: couldn't process source due to parse error,'import' and 'export' may appear only with 'sourceType: module' (2:0)
 @ multi (webpack)-dev-server/client?http://localhost:3000 ./src/app.module.js

ERROR in ./src/vendor.module.js
Module build failed: error: couldn't process source due to parse error,'import' and 'export' may appear only with 'sourceType: module' (5:0)
 @ multi (webpack)-dev-server/client?http://localhost:3000 ./src/vendor.module.js

These are the modules to import, can someone tell me what the error is?

app.module.js

// for loading styles we need to load main scss file
import styles from './assets/styles.scss';

// loading shared module
import './modules/common/common.module';
import './modules/login/login.module';
import './modules/dashboard/dashboard.module';
import './modules/investment/investment.module';
import './modules/transfer/transfer.module';
import Config from './modules/common/factories/Config';


import './modules/user/user.module';
import './modules/product/product.module';
...

vendor.module.js

/**
 * Load all 3rd party imports here so it'll be
 * directly included in vendor.bundle.js file.
 */
import 'angular-ui-router';
import 'angular-resource';
import 'angular-animate';
import 'angular-aria';
import 'angular-input-masks';

import 'jquery';
import 'popper.js';
import 'bootstrap/dist/js/bootstrap.min.js';
import 'angular-material/angular-material';
import 'angular-wizard/dist/angular-wizard.min.js';
import 'md-steppers/dist/md-steppers.min.js';
import 'angular-ui-bootstrap';
import 'jquery-knob/dist/jquery.knob.min.js';
import 'ng-ui-knob/dist/ng-knob.js';
import './assets/lib/ngMask.min.js';

The command I use to compile is the following

node_modules/.bin/webpack --progress

Source: AngularJS Questions