feat: util methods to manipulate graphqlTimeRange (#1271)

* feat: util methods to manipulate graphqlTimeRange

Author: arjunlalb

projects/observability/src/public-api.ts

@@ -382,3 +382,6 @@ export * from './shared/components/label-detail/label-detail.module';
 // Bar Gauge
 export * from './shared/components/bar-gauge/bar-gauge.component';
 export * from './shared/components/bar-gauge/bar-gauge.module';
+
+// Time Range utils
+export * from './shared/utils/time-range';

projects/observability/src/shared/graphql/model/schema/timerange/graphql-time-range.ts

@@ -1,4 +1,4 @@
-import { TimeRange } from '@hypertrace/common';
+import { TimeDuration, TimeRange, TimeUnit } from '@hypertrace/common';
 
 export class GraphQlTimeRange {
   public static fromTimeRange(timeRange: Pick<TimeRange, 'startTime' | 'endTime'>): GraphQlTimeRange {
@@ -13,4 +13,11 @@ export class GraphQlTimeRange {
       endTime: typeof this.to === 'number' ? new Date(this.to) : this.to
     };
   }
+
+  public asTimeDuration(): TimeDuration {
+    return new TimeDuration(
+      this.asArgumentObject().endTime.getTime() - this.asArgumentObject().startTime.getTime(),
+      TimeUnit.Millisecond
+    );
+  }
 }

projects/observability/src/shared/utils/time-range.test.ts

@@ -0,0 +1,11 @@
+import { GraphQlTimeRange } from '../graphql/model/schema/timerange/graphql-time-range';
+import { getPreviousTimeRange } from './time-range';
+
+describe('Time Range Util', () => {
+  const oneHourRange = new GraphQlTimeRange(new Date(1637298000000), new Date(1637301600000));
+  test('computes previous time window as expected', () => {
+    const previousTimeRange = getPreviousTimeRange(oneHourRange);
+    expect(new Date(previousTimeRange.from).getTime()).toEqual(1637294400000);
+    expect(new Date(previousTimeRange.to).getTime()).toEqual(1637298000000);
+  });
+});

projects/observability/src/shared/utils/time-range.ts

@@ -0,0 +1,11 @@
+import { TimeDuration, TimeUnit } from '@hypertrace/common';
+import { GraphQlTimeRange } from '../graphql/model/schema/timerange/graphql-time-range';
+
+export const getPreviousTimeRange = (timeRange: GraphQlTimeRange): GraphQlTimeRange => {
+  const requiredDuration: TimeDuration = timeRange.asTimeDuration();
+
+  return new GraphQlTimeRange(
+    timeRange.asArgumentObject().startTime.getTime() - requiredDuration.getAmountForUnit(TimeUnit.Millisecond),
+    timeRange.asArgumentObject().startTime.getTime()
+  );
+};