Hello,
I built a free module that does allow you to add multiple products to the cart (currently, the quantity will always be 1). It has only been tested in PrestaShop 8 with the base theme.
The flow is pretty simple. If the module can find products in a page, it will add a checkbox for each one of them and a button for adding them to the cart. Once clicked, the button will do an AJAX request to a controller that will add the products to the cart.
Most of the logic is built using TypeScript. Let me know if you have any questions.
Here is the GitHub link: https://github.com/andreihumulescu/ps-add-multiple-products and here is the zip that you can upload in your admin: https://github.com/andreihumulescu/ps-add-multiple-products/releases/tag/v1.0.0
If you find any issues, just let me know and I'll address them in a future version.
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