nextjs/no-unwanted-polyfillio Correctness ​
What it does ​
Prevent duplicate polyfills from Polyfill.io.
Why is this bad? ​
You are using polyfills from Polyfill.io and including polyfills already shipped with Next.js. This unnecessarily increases page weight which can affect loading performance.
Example ​
javascript
<script src='https://polyfill.io/v3/polyfill.min.js?features=Array.prototype.copyWithin'></script>
<script src='https://polyfill.io/v3/polyfill.min.js?features=WeakSet%2CPromise%2CPromise.prototype.finally%2Ces2015%2Ces5%2Ces6'></script>