Disable checkout if all products do not share same tag Shopify - shopify

Question

I have a custom checkout experience in my Shopify store that I only want to allow if all products in the cart contain the tag "test"
This is the function I currently have, which seems to only work with a single item in the cart.
function productTags() {
{%- assign tagEnabled = false -%}
return {
{%- for item in cart.items -%}
{%- if item.product.tags contains 'test' -%}
"{{ item.product.tags }}": {{ item.quantity | json }}
{%- assign tagEnabled = true -%}
{%- endif -%}
{%- endfor -%}
};
}
this line ( "{{ item.product.tags }}": {{ item.quantity | json }}) is only there for display in the console when testing this. I can remove that if necessary.
How can I expand this to look for all item tags in the cart, and only assign the tagEnabled variable to true if all of them have the same tag?
Thanks in advance!

Answer 1

It looks like you are trying to mix Liquid with Javascript, which can make coding confusing. I would recommend splitting your code into two parts: one where you collect your Liquid variables and assign them to Javascript variables (and I see you are using the json filter to do that already, which is awesome - that filter guarantees that your variable output will be in a Javascript-legal format), and the second part where you write your Javascript code without any Liquid brackets getting in the way. (This is especially helpful if you are using a code editor with any syntax or error highlighting)
Let me know if the following helps you get the information you need:
// The Liquid filter 'map' lets you drill into nested object properties. We can use this to get an array of tag arrays.
// The JSON Liquid filter will turn any Liquid variable into a legal Javascript variable.
const itemProductTags = {{ cart.items | map: 'product'| map: 'tags' | json }}
// Check on our variables
console.log('All product tag arrays', itemProductTags)
console.log('Results of tagCheck()', tagCheck(itemProductTags, 'test') )
function tagCheck(tagsList, targetTag){
// Checks to see if the targetTag appears in all, some or none of the tag arrays.
// tagsList will be an array of arrays
var targetInAny = false;
var targetInAll = true;
for(var i=0; i<tagsList.length; i++){
var tags = tagsList[i];
if(tags.indexOf(targetTag) != -1){
// Found the tag - this targetTag appears in at least one product-tag list
targetInAny = true;
}
else{
// Did not find the tag - this targetTag is NOT in every product-tag list
targetInAll = false;
}
}
// Returns an object specifying if we found the target in any, all or none of the lists
return { targetInAny: targetInAny, targetInAll: targetInAll, targetInNone: !targetInAny }
}