UglifyJs: Unexpected token: operator (>)

When running npm run production I get the following error:

/js/listing.js from UglifyJs
Unexpected token: operator (>) [./~/bootstrap/js/src/dropdown.js:11,0][/js/listing.js:3302,23]

I’ve tried deleting node_modules without any luck, same goes for installing:

yarn add --dev git+https://github.com/mishoo/UglifyJS2.git#harmony

Arrow function seem to be the issue, line 11 of dropdown.js is:

const Dropdown = (($) => {

I don’t have a .babelrc file.

laravel-mix@0.11.4
Node: v7.9.0
NPM: 4.5.0
macOS: 10.12.4

[Shchepotin]

Same problem.

[hozefaj]

For webpack v3 onwards the aliasing for UglifyJS is changed. Refer https://github.com/webpack-contrib/uglifyjs-webpack-plugin.

So for me modifying my webpack.config.js from to use new UglifyJsPlugin() rather than new webpack.optimize.UglifyJsPlugin() fixed the issue.

Reference: https://github.com/joeeames/WebpackFundamentalsCourse/issues/3#issuecomment-352541826