[JavaScript]useAppMetafields

let j,productId;
const cartLines = useCartLines();
const appMetafields = useAppMetafields();
if(appMetafields.length){
  cartLines.forEach((cartLine,i)=>{
    productId = cartLine.merchandise.product.id.split("/").pop();
    for(j=0;j<appMetafields.length;j++){
      if(appMetafields[j].target.id === productId){
        if(appMetafields[j].metafield.key === "metafieldKey" && appMetafields[j].metafield.value === "metafieldValue"){
          //処理
        }
        break;
      }
    }
  });
}