Exception when running "npm run watch-poll" after upgrading to 5.7

I had some weird issues with Vue still being called when using React as well. Have you tried deleting your node_modules folder and the package.lock.json file and doing a fresh npm install?

@BILLRIESS - Yes, I did /-:

To get around this issue I have changed a line in node_modules\laravel-mix\src\components\JavaScript.js:10

from

JavaScript.vueWebpackConfigApplied = false;

to

JavaScript.vueWebpackConfigApplied = true;

this var is being used in line 88, but it's hard for me to understand it:

    /**
     * Override the generated webpack configuration.
     *
     * @param {Object} webpackConfig
     */
    webpackConfig(webpackConfig) {
        if (!JavaScript.vueWebpackConfigApplied) {
            this.vue.webpackConfig(webpackConfig);
        }

        JavaScript.vueWebpackConfigApplied = true;
    }

I'm new to Laravel, if there's any other venue to post this issue and have a Laravel dev take a look, please let me know

Post your webpack.mix.js and your package.json.

webpack.mix.js:

mix.webpackConfig({
    module: {
        rules: [{
            test: /\.css$/,
            loader: 'style-loader!css-loader'
        }]
    }});

mix.react('resources/js/d.js', 'public/js');
mix.sass('resources/sass/dashboard/d.scss', 'public/css');

mix.sass('resources/sass/app/a.scss', 'public/css')
.js('resources/js/a.js', 'public/js');


mix.browserSync({
    // proxy: 'local.trans',
    proxy: 'my.local.trans',
    open: false,
    scrollProportionally: false,
});

package.json:

{
  "private": true,
  "scripts": {
    "dev": "npm run development",
    "development": "node node_modules/cross-env/dist/bin/cross-env.js NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
    "watch": "npm run development -- --watch",
    "watch-poll": "npm run watch -- --watch-poll",
    "hot": "node node_modules/cross-env/dist/bin/cross-env.js NODE_ENV=development node_modules/webpack-dev-server/bin/webpack-dev-server.js --inline --hot --config=node_modules/laravel-mix/setup/webpack.config.js",
    "prod": "npm run production",
    "production": "node node_modules/cross-env/dist/bin/cross-env.js NODE_ENV=production node_modules/webpack/bin/webpack.js --no-progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js"
  },
  "devDependencies": {
    "@babel/preset-react": "^7.0.0",
    "@uppy/core": "^0.29.0",
    "@uppy/dashboard": "^0.29.0",
    "@uppy/dropbox": "^0.29.0",
    "@uppy/google-drive": "^0.29.0",
    "@uppy/react": "^0.29.0",
    "@uppy/url": "^0.29.0",
    "@uppy/xhr-upload": "^0.29.0",
    "axios": "^0.18",
    "bootstrap": "^4.2.1",
    "browser-sync": "^2.26.3",
    "browser-sync-webpack-plugin": "^2.0.1",
    "cross-env": "^5.1",
    "css-loader": "^2.1.0",
    "jquery": "^3.2",
    "laravel-mix": "^4.0.7",
    "lodash": "^4.17.5",
    "moment": "^2.22.2",
    "node-sass": "^4.11.0",
    "nprogress": "^0.2.0",
    "popper.js": "^1.14.5",
    "prop-types": "^15.6.2",
    "react": "^16.7.0",
    "react-dom": "^16.7.0",
    "react-icons": "^3.2.2",
    "react-router-dom": "^4.3.1",
    "react-spinners": "^0.3.3",
    "react-sticky-el": "^1.0.20",
    "reactstrap": "^7.1.0",
    "resolve-url-loader": "^2.3.1",
    "sass": "^1.15.2",
    "sass-loader": "^7.1.0",
    "slate": "^0.41.2",
    "slate-react": "^0.18.10",
    "video.js": "^7.4.1",
    "vue": "^2.5.17",
    "vue-template-compiler": "^2.5.22"
  }
}

Try removing vue out of your npm dependancies.

npm uninstall vue --save-dev still throws the same exception...