Grafana live: Add tests and missing code to amendTable (#89031)

* Grafana live: Add tests and missing code to amendTable

* Betterer

.betterer.results

@@ -4653,7 +4653,8 @@ exports[`better eslint`] = {
       [0, 0, 0, "Do not use any type assertions.", "1"],
       [0, 0, 0, "Do not use any type assertions.", "2"],
       [0, 0, 0, "Do not use any type assertions.", "3"],
-      [0, 0, 0, "Do not use any type assertions.", "4"]
+      [0, 0, 0, "Do not use any type assertions.", "4"],
+      [0, 0, 0, "Do not use any type assertions.", "5"]
     ],
     "public/app/features/logs/components/InfiniteScroll.tsx:5381": [
       [0, 0, 0, "No untranslated strings. Wrap text with <Trans />", "0"]

public/app/features/live/data/amendTimeSeries.test.ts

@@ -0,0 +1,123 @@
+import { Table, amendTable } from "./amendTimeSeries";
+
+describe('amendTable', () => {
+  it('should append nextTable when there is no overlap (nextTable after prevTable)', () => {
+    const prevTable: Table = [
+      [1, 2, 5],
+      ['a', 'b', 'e'],
+    ];
+    const nextTable: Table = [
+      [6, 7, 8],
+      ['f', 'g', 'h'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual([
+      [1, 2, 5, 6, 7, 8],
+      ['a', 'b', 'e', 'f', 'g', 'h'],
+    ]);
+  });
+
+  it('should prepend nextTable when there is no overlap (nextTable before prevTable)', () => {
+    const prevTable: Table = [
+      [3, 4, 5],
+      ['c', 'd', 'e'],
+    ];
+    const nextTable: Table = [
+      [1, 2],
+      ['a', 'b'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual([
+      [1, 2, 3, 4, 5],
+      ['a', 'b', 'c', 'd', 'e'],
+    ]);
+  });
+
+  it('should fully replace prevTable when nextTable covers entire range', () => {
+    const prevTable: Table = [
+      [3, 4, 5],
+      ['c', 'd', 'e'],
+    ];
+    const nextTable: Table = [
+      [1, 2, 3, 4, 5, 6],
+      ['a', 'b', 'c', 'd', 'e', 'f'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual(nextTable);
+  });
+
+  it('should partially replace prevTable when nextTable is within range', () => {
+    const prevTable: Table = [
+      [1, 2, 3, 4, 5],
+      ['a', 'b', 'c', 'd', 'e'],
+    ];
+    const nextTable: Table = [
+      [3, 4],
+      ['x', 'y'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual([
+      [1, 2, 3, 4, 5],
+      ['a', 'b', 'x', 'y', 'e'],
+    ]);
+  });
+
+  it('should append nextTable with overlap', () => {
+    const prevTable: Table = [
+      [1, 2, 5],
+      ['a', 'b', 'e'],
+    ];
+    const nextTable: Table = [
+      [2, 3, 6],
+      ['b', 'c', 'f'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual([
+      [1, 2, 3, 6],
+      ['a', 'b', 'c', 'f'],
+    ]);
+  });
+
+  it('should prepend nextTable with overlap', () => {
+    const prevTable: Table = [
+      [3, 4, 5],
+      ['c', 'd', 'e'],
+    ];
+    const nextTable: Table = [
+      [1, 4],
+      ['a', 'd'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual([
+      [1, 4, 5],
+      ['a', 'd', 'e'],
+    ]);
+  });
+
+  it('should handle empty prevTable', () => {
+    const prevTable: Table = [[]];
+    const nextTable: Table = [
+      [1, 2, 3],
+      ['a', 'b', 'c'],
+    ];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual(nextTable);
+  });
+
+  it('should handle empty nextTable', () => {
+    const prevTable: Table = [
+      [1, 2, 3],
+      ['a', 'b', 'c'],
+    ];
+    const nextTable: Table = [[]];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual(prevTable);
+  });
+
+  it('should handle both tables being empty', () => {
+    const prevTable: Table = [[]];
+    const nextTable: Table = [[]];
+    const result = amendTable(prevTable, nextTable);
+    expect(result).toEqual([[]]);
+  });
+});

public/app/features/live/data/amendTimeSeries.ts

@@ -35,6 +35,18 @@ export function amendTable(prevTable: Table, nextTable: Table): Table {
       }
       // partial replace
       else if (nStart > pStart && nEnd < pEnd) {
+        // partial replace
+        let startIdx = closestIdx(nStart, prevTimes);
+        startIdx = prevTimes[startIdx] < nStart ? startIdx + 1 : startIdx;
+        let endIdx = closestIdx(nEnd, prevTimes);
+        endIdx = prevTimes[endIdx] > nEnd ? endIdx - 1 : endIdx;
+
+        outTable = prevTable.map((_, i) =>
+          prevTable[i]
+            .slice(0, startIdx)
+            .concat(nextTable[i])
+            .concat(prevTable[i].slice(endIdx + 1))
+        ) as Table;
       }
       // append, with overlap
       else if (nStart >= pStart) {