If you need to sortBy or apply a customRanking attribute based on a date in Shopify, you will find that the date formats on your product data are alphanumeric strings. This is the format that is provided on the product data that we request from Shopify.
Because Algolia doesn’t interpret dates as ISO 8601 strings (such as “2008-09-15T15:53:00”), you must convert your dates into Unix timestamps (numeric values such as 1221486780) before sorting them. You can find more information on this here.
When you need to enrich your product data with an additional attr/value, you can implement metafields. In this situation, you can use the number type and set up the sorting order in the plugin directly:
Algolia plugin > Search options > InstantSearch > Sort orders