how to add item to cart by cart.js before submit shop pay

[maigan]

look picture, how to add item to cart by cart.js before submit shop pay

[wisn_shaftler]

Do you need to add another product to cart when someone click on this shop pay button? like if someone in product "A" page and when they click on the "shop pay" button you need to add product "b" to cart and let them to checkout with product A and B ?

[maigan]

Not exactly.
The buyer has customized multiple products by himself (we have developed design tools that can customize multiple products), and needs to add them to the shopping cart and check out at once.
Therefore, we really need to add them all to the shopping cart before the quick checkout! ! How can we do it?

[wisn_shaftler]

normaly you can add property input inside of the product form like

<form action="/cart/add">
<input type="hidden" name="form_type" value="product">
<input type="hidden" name="id" value="41324315803699" class="product-variant-id">
<input type="hidden" name="properties['my custom value']" value="my custom value" >
</form>

adding input like the properties code, you can pass the value to checkout page

[maigan]

No, we have implemented the form solution you mentioned, but only one item can be purchased.
We need to add multiple items to the shopping cart (customer completes DIY multiple products).
For example, for a shirt, the buyer uploads picture 1 and saves a work, and then continues to upload picture 2 to complete another work. This is just an example. In fact, the DIY process is richer, but the color of the shirt is different. In the end, each save is based on a variant, and each variant needs to be added to the shopping cart to complete the purchase.
Therefore, we need to submit multiple variants and corresponding quantities in this form.
Or any solution is fine. The above is just an expression of our needs.