fix skipping recipe list bug

server/services/recipe/recipe.go

@@ -141,6 +141,26 @@ func (rs *recipeService) GetRecipeDetailMat(request *contracts.RecipeDetailReque
 					WaterYield:     v.WaterYield,
 				})
 				break
+			} else if v.MaterialPathId == 0 {
+				// this is empty material slot
+				result.Result = append(result.Result, contracts.RecipeDetailMat{
+					StringParam:    "",
+					IsUse:          false,
+					MaterialID:     0,
+					Name:           "",
+					MixOrder:       0,
+					FeedParameter:  0,
+					FeedPattern:    0,
+					MaterialPathId: 0,
+					PowderGram:     0,
+					PowderTime:     0,
+					StirTime:       0,
+					SyrupGram:      0,
+					SyrupTime:      0,
+					WaterCold:      0,
+					WaterYield:     0,
+				})
+				break
 			}
 		}
 	}