refactor: simplify sync system logic

techmatters · Oct 24, 2024 · 12221d1 · 12221d1
1 parent ca1c094
commit 12221d1
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Showing 2 changed files with 20 additions and 36 deletions.
diff --git a/dev-client/src/model/sync/sync.test.ts b/dev-client/src/model/sync/sync.test.ts
@@ -18,7 +18,6 @@
 import {
   ChangeRecords,
   getChanges,
-  getRevisionId,
   getUnsyncedRecords,
   getUpToDateResults,
   isUnsynced,
@@ -32,21 +31,11 @@ describe('sync', () => {
     jest.useFakeTimers().setSystemTime(new Date('2020-01-01'));
   });
 
-  describe('getRevisionId', () => {
-    test('zero for undefined revision', () => {
-      expect(getRevisionId(undefined)).toEqual(0);
-    });
-
-    test('zero for empty revision', () => {
-      expect(getRevisionId({})).toEqual(0);
+  describe('nextRevisionId', () => {
+    test('assumes zero initial value', () => {
+      expect(nextRevisionId(undefined)).toEqual(1);
     });
 
-    test('value for revision', () => {
-      expect(getRevisionId({revisionId: 123})).toEqual(123);
-    });
-  });
-
-  describe('nextRevisionId', () => {
     test('increments by one', () => {
       expect(nextRevisionId(1)).toEqual(2);
     });
@@ -202,8 +191,11 @@ describe('sync', () => {
 
     test('handles results with no change records', () => {
       expect(
-        getUpToDateResults({}, {a: {revisionId: 0}, b: {revisionId: 1}}),
-      ).toEqual({a: {revisionId: 0}});
+        getUpToDateResults(
+          {},
+          {a: {revisionId: undefined}, b: {revisionId: 1}},
+        ),
+      ).toEqual({a: {revisionId: undefined}});
     });
   });
 });
diff --git a/dev-client/src/model/sync/sync.ts b/dev-client/src/model/sync/sync.ts
@@ -45,16 +45,10 @@ export type SyncResult<T> = {
 
 export const INITIAL_REVISION_ID = 0;
 
-export const getRevisionId = <T>(
-  record?: ChangeRecord<T>,
-): ChangeRevisionId => {
-  return record?.revisionId ?? INITIAL_REVISION_ID;
-};
-
 export const nextRevisionId = (
-  revisionId: ChangeRevisionId,
+  revisionId?: ChangeRevisionId,
 ): ChangeRevisionId => {
-  return revisionId + 1;
+  return (revisionId ?? INITIAL_REVISION_ID) + 1;
 };
 
 export const getChanges = <T>(
@@ -87,15 +81,14 @@ export const markChanged = <T>(
   at: ChangeTimestamp,
 ) => {
   const prevRecord = getChange(records, id);
-  const prevRevisionId = getRevisionId(prevRecord);
-  const revisionId = nextRevisionId(prevRevisionId);
+  const revisionId = nextRevisionId(prevRecord.revisionId);
   records[id] = {
     revisionId: revisionId,
     lastModifiedAt: at,
 
-    lastSyncedRevisionId: prevRecord?.lastSyncedRevisionId,
-    lastSyncedData: prevRecord?.lastSyncedData,
-    lastSyncedAt: prevRecord?.lastSyncedAt,
+    lastSyncedRevisionId: prevRecord.lastSyncedRevisionId,
+    lastSyncedData: prevRecord.lastSyncedData,
+    lastSyncedAt: prevRecord.lastSyncedAt,
   };
 };
 
@@ -116,10 +109,9 @@ export const markSynced = <T>(
   at: ChangeTimestamp,
 ) => {
   const prevRecord = getChange(records, id);
-  const prevRevisionId = getRevisionId(prevRecord);
   records[id] = {
-    revisionId: prevRevisionId,
-    lastModifiedAt: prevRecord?.lastModifiedAt,
+    revisionId: prevRecord.revisionId,
+    lastModifiedAt: prevRecord.lastModifiedAt,
     lastSyncedAt: at,
     lastSyncedRevisionId: result.revisionId,
     lastSyncedData: result.data,
@@ -146,7 +138,7 @@ export const isUnsynced = <T>(record: ChangeRecord<T>): boolean => {
     return true;
   } else {
     /* Unsynced changes if the record's current revision is not the last-synced one */
-    return getRevisionId(record) !== record.lastSyncedRevisionId;
+    return record.revisionId !== record.lastSyncedRevisionId;
   }
 };
 
@@ -156,14 +148,14 @@ export const getUpToDateResults = <T>(
 ): SyncResults<T> => {
   return Object.fromEntries(
     Object.entries(results).filter(([id, result]) =>
-      isUpToDate(records[id], result),
+      isUpToDate(getChange(records, id), result),
     ),
   );
 };
 
 export const isUpToDate = <T>(
-  record: ChangeRecord<T> | undefined,
+  record: ChangeRecord<T>,
   result: SyncResult<T>,
 ): boolean => {
-  return getRevisionId(record) === result.revisionId;
+  return record.revisionId === result.revisionId;
 };