Shopify Quantity Limiter (Timber Framework Files)
Working Demo:
Product A (Single Variant): Bjml Mystic Water Clean This product has different sizes and you can find the max quantity allowed for each variant in the product description section.
Product B (Multiple Variants): Bobby Straight Recycled Renegade Mens Jean This product has multiple variants (Size, Leg) and you can find the max quantity allowed for each variant combination in the product description section.
Blog Post explaining all the steps: http://byaman.com/maximum-quantity-limiter-shopify/