Applying discounts based on customer tags in Shopify

This guide assumes you have access to the Shopify script editor which comes with Shopify Plus.

First we'll initialize the customer in the ruby source code:

customer = Input.cart.customer

Then we'll want to make the function that applies the discount based on the passed parameter

def applyDiscount (message, discountAmount)

In the function we'll loop through each line item in the cart and apply the discount by multiplying the line item price by the discount amount

Input.cart.line_items.each do |line_item|
line_item.change_line_price(line_item.line_price * discountAmount, message: "#{message}")
end

If we wanted the tag discount to only apply on certain products we can wrap the condition with an if statement

Input.cart.line_items.each do |line_item|
product = line_item.variant.product.product_type
if product == "Test"
line_item.change_line_price(line_item.line_price * discountAmount, message: "#{message}")
end
end

Now that the function is defined we'll need to determine with the customer is logged in

if customer

Now we'll check for the specific tag that we are looking for

if customer
  if customer.tags.include?("TestDiscount")
  #apply discount on TestDiscount tag for 50% on products
  applyDiscount "Test Discount Applied", 0.5
  end
end

And that's it! The test discount will apply 50% to all products if the tag is present on the customer logged in. To avoid overlapping with discount codes inputted you will need to check if the discount code is null or not first.

Done.

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