feat(core): add era summary to epoch slots calc return value

BREAKING CHANGE: remove unused type EpochSlots
input-output-hk · Oct 26, 2023 · 44f2216 · 44f2216
1 parent a00a77d
commit 44f2216
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Showing 2 changed files with 39 additions and 12 deletions.
diff --git a/packages/core/src/util/slotCalc.ts b/packages/core/src/util/slotCalc.ts
@@ -1,6 +1,7 @@
 import { CustomError } from 'ts-custom-error';
 import { EpochNo, NetworkMagics, Slot } from '../Cardano';
 import { EraSummary } from '../CardanoNode';
+import { NetworkInfoProvider } from '../Provider/NetworkInfoProvider';
 import groupBy from 'lodash/groupBy';
 import last from 'lodash/last';
 import memoize from 'lodash/memoize';
@@ -119,30 +120,50 @@ export const createSlotEpochInfoCalc = (eraSummaries: EraSummary[]) => {
 };
 
 /**
- * @returns first slot of the epoch
+ * The actual implementation, _memoized_ by `epochSlotsCalc` or directly used by `epochSlotsCalcFactory`.
+ *
+ * @param epochNo epoch number
+ * @param eraSummaries era summaries array
+ * @returns `eraSummary`, `firstSlot` and `lastSlot` of given epoch
  */
-export const epochSlotsCalc = memoize((epochNo: EpochNo, eraSummaries: EraSummary[]) => {
+const epochSlotsCalcImplementation = (epochNo: EpochNo, eraSummaries: EraSummary[]) => {
   let atEpoch = 0;
   let atSlot = eraSummaries[0].start.slot;
   let eraSummaryIdx = 0;
   const maxEraSummaryIdx = eraSummaries.length - 1;
+
   while (atEpoch !== epochNo) {
     atSlot += eraSummaries[eraSummaryIdx].parameters.epochLength;
     atEpoch++;
+
     if (eraSummaryIdx < maxEraSummaryIdx && atSlot >= eraSummaries[eraSummaryIdx + 1].start.slot) {
       eraSummaryIdx++;
     }
   }
+
+  const eraSummary = eraSummaries[eraSummaryIdx];
+
   return {
+    eraSummary,
     firstSlot: Slot(atSlot),
-    lastSlot: Slot(atSlot + eraSummaries[eraSummaryIdx].parameters.epochLength - 1)
+    lastSlot: Slot(atSlot + eraSummary.parameters.epochLength - 1)
   };
-});
+};
 
 /**
- * @returns first and last slot numbers of the epoch
+ * @returns `eraSummary`, `firstSlot` and `lastSlot` of given epoch
  */
-export type EpochSlots = ReturnType<typeof epochSlotsCalc>;
+export const epochSlotsCalc = memoize(epochSlotsCalcImplementation);
+
+/**
+ * Creates an `epochSlotsCalc` version able to get the epoch summaries from a
+ * `NetworkInfoProvider` by itself.
+ *
+ * @returns the `epochSlotsCalc` function
+ */
+export const epochSlotsCalcFactory = memoize((provider: NetworkInfoProvider) =>
+  memoize(async (epochNo: EpochNo) => epochSlotsCalcImplementation(epochNo, await provider.eraSummaries()))
+);
 
 /**
  * @throws EraSummaryError

diff --git a/packages/core/test/util/slotCalc.test.ts b/packages/core/test/util/slotCalc.test.ts
@@ -69,31 +69,36 @@ describe('slotCalc utils', () => {
   describe('epochStartCalc', () => {
     describe('preprod', () => {
       it('correctly computes 1st slot of the 0th epoch', () => {
-        const { firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(0), preprodEraSummaries);
+        const { eraSummary, firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(0), preprodEraSummaries);
+        expect(eraSummary).toBe(preprodEraSummaries[0]);
         expect(firstSlot).toBe(0);
         expect(lastSlot).toBe(21_599);
       });
 
       it('correctly computes 1st slot of some Byron epoch', () => {
-        const { firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(2), preprodEraSummaries);
+        const { eraSummary, firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(2), preprodEraSummaries);
+        expect(eraSummary).toBe(preprodEraSummaries[0]);
         expect(firstSlot).toBe(43_200);
         expect(lastSlot).toBe(64_799);
       });
 
       it('correctly computes 1st slot of last Byron epoch', () => {
-        const { firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(3), preprodEraSummaries);
+        const { eraSummary, firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(3), preprodEraSummaries);
+        expect(eraSummary).toBe(preprodEraSummaries[0]);
         expect(firstSlot).toBe(64_800);
         expect(lastSlot).toBe(86_399);
       });
 
       it('correctly computes 1st slot of first Shelley epoch', () => {
-        const { firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(4), preprodEraSummaries);
+        const { eraSummary, firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(4), preprodEraSummaries);
+        expect(eraSummary).toBe(preprodEraSummaries[1]);
         expect(firstSlot).toBe(86_400);
         expect(lastSlot).toBe(518_399);
       });
 
       it('correctly computes 1st slot of some epoch in the middle of era summaries', () => {
-        const { firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(5), preprodEraSummaries);
+        const { eraSummary, firstSlot, lastSlot } = epochSlotsCalc(Cardano.EpochNo(5), preprodEraSummaries);
+        expect(eraSummary).toBe(preprodEraSummaries[2]);
         expect(firstSlot).toBe(518_400);
         expect(lastSlot).toBe(950_399);
       });
@@ -102,7 +107,8 @@ describe('slotCalc utils', () => {
         const epoch = Cardano.EpochNo(20);
         const expectedFirstSlot = Cardano.Slot(6_998_400);
         const expectedLastSlot = Cardano.Slot(7_430_399);
-        const { firstSlot, lastSlot } = epochSlotsCalc(epoch, preprodEraSummaries);
+        const { eraSummary, firstSlot, lastSlot } = epochSlotsCalc(epoch, preprodEraSummaries);
+        expect(eraSummary).toBe(preprodEraSummaries[5]);
         expect(firstSlot).toBe(expectedFirstSlot);
         expect(lastSlot).toBe(expectedLastSlot);
         const epochSlotCalc = createSlotEpochCalc(preprodEraSummaries);