@pd76 thanks for the reply. Yes, I found the cause to be that I upgraded a dependency (feathersJS client v3) whose dist is in ES6. So for now, I downgraded it. But I will take a look at babel-minify-webpack soon. Thank you.
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RE: Quasar Build: ERROR in js/vendor.js from UglifyJs (Unexpected token: name (EventEmitter))