Resilient Import Maps - Better Theme Development and Beyond (2025) - Shopify

This post details Shopify's collaboration with the web platform to implement a reconciliation mechanism for import maps. This mechanism allows for multiple import maps and modules to load before or between import maps, resolving conflicts by merging new maps into a global representation. This was achieved by modifying the merge algorithm to drop rules that impact already loaded modules or conflict with existing rules. The implementation in Chromium and WebKit, along with the es-modules-shim polyfill, ensures broader browser support.