Add aggregation sum util

plugins/cost-insights/src/utils/change.ts

@@ -23,6 +23,7 @@ import {
   MetricData,
   Duration,
   DEFAULT_DATE_FORMAT,
+  DateAggregation,
 } from '../types';
 import dayjs, { OpUnitType } from 'dayjs';
 import duration from 'dayjs/plugin/duration';
@@ -54,9 +55,9 @@ export function getComparedChange(
   duration: Duration,
   lastCompleteBillingDate: string, // YYYY-MM-DD,
 ): ChangeStatistic {
-  const ratio = dailyCost.change.ratio - metricData.change.ratio;
+  const ratio = dailyCost.change!.ratio - metricData.change.ratio;
   const previousPeriodTotal = getPreviousPeriodTotalCost(
-    dailyCost,
+    dailyCost.aggregation,
     duration,
     lastCompleteBillingDate,
   );
@@ -67,7 +68,7 @@ export function getComparedChange(
 }
 
 export function getPreviousPeriodTotalCost(
-  dailyCost: Cost,
+  aggregation: DateAggregation[],
   duration: Duration,
   inclusiveEndDate: string,
 ): number {
@@ -83,7 +84,7 @@ export function getPreviousPeriodTotalCost(
   const nextPeriodStart = dayjs(startDate).add(amount, type);
 
   // Add up costs that incurred before the start of the next period.
-  return dailyCost.aggregation.reduce((acc, costByDate) => {
+  return aggregation.reduce((acc, costByDate) => {
     return dayjs(costByDate.date).isBefore(nextPeriodStart)
       ? acc + costByDate.amount
       : acc;

plugins/cost-insights/src/utils/sum.ts

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { DateAggregation } from '../types';
+
+export const aggregationSum = (aggregation: DateAggregation[]) =>
+  aggregation.reduce((total, curAgg) => total + curAgg.amount, 0);