We are using WooCommerce official simple logic from: GitHub and using reactJs/NextJs.
https://example.com/wp-json/wc/v3/products/109/variations?consumer_key=ck_6043dd55fccc284e03f8csdcb89f6c75d3e12854b24ff6
&consumer_secret=cs_cd0ef3822f151ae01xc54dce9c2be22cdcsc6f513d2663
next: we can use “variations_ProductData” in return and use to Map() method.
variations products fetch: Live Demo and we are Offering a completed project: Download