fix: fixed infinite loop in expandUniqueDateBlocks()

- identified and fixed scenario where expandUniqueDateBlocks() could loop infinitely

packages/date/src/lib/date/date.block.spec.ts

@@ -1,8 +1,8 @@
 import { expectFail, itShouldFail } from '@dereekb/util/test';
 import { DateRange, DateRangeInput } from './date.range';
 import { addDays, addHours, addMinutes, setHours, setMinutes, startOfDay, endOfDay, addSeconds, addMilliseconds, millisecondsToHours, minutesToHours } from 'date-fns';
-import { DateBlock, dateBlockDayOfWeekFactory, DateBlockIndex, dateBlockIndexRange, dateBlockRange, DateBlockRangeWithRange, dateBlocksExpansionFactory, dateBlocksInDateBlockRange, dateBlockTiming, DateBlockTiming, expandDateBlockRange, expandUniqueDateBlocks, getCurrentDateBlockTimingOffset, getCurrentDateBlockTimingStartDate, groupToDateBlockRanges, groupUniqueDateBlocks, isValidDateBlockTiming, UniqueDateBlockRange } from './date.block';
-import { MS_IN_DAY, MINUTES_IN_DAY, range, RangeInput, Hours, Day } from '@dereekb/util';
+import { DateBlock, dateBlockDayOfWeekFactory, DateBlockIndex, dateBlockIndexRange, dateBlockRange, DateBlockRangeWithRange, dateBlocksExpansionFactory, dateBlocksInDateBlockRange, dateBlockTiming, DateBlockTiming, expandDateBlockRange, expandUniqueDateBlocks, getCurrentDateBlockTimingOffset, getCurrentDateBlockTimingStartDate, groupToDateBlockRanges, groupUniqueDateBlocks, isValidDateBlockTiming, sortDateBlockRanges, UniqueDateBlockRange } from './date.block';
+import { MS_IN_DAY, MINUTES_IN_DAY, range, RangeInput, Hours, Day, expandIndexSet } from '@dereekb/util';
 import { removeMinutesAndSeconds } from './date';
 
 describe('getCurrentDateBlockTimingOffset()', () => {
@@ -685,6 +685,23 @@ describe('expandUniqueDateBlocks', () => {
             });
           });
         });
+
+        describe('with larger first followed by smaller', () => {
+          it('incumbent value should be retained.', () => {
+            const blocks = [
+              { i: 0, to: 5, value: 'a' },
+              { i: 0, value: 'b' }
+            ];
+            const result = overwriteNextExpand(blocks);
+
+            expect(result.blocks.length).toBe(1);
+            expect(result.discarded.length).toBe(1);
+            expect(result.discarded[0].value).toBe(blocks[1].value);
+            expect(result.blocks[0].value).toBe(blocks[0].value);
+            expect(result.blocks[0].i).toBe(blocks[0].i);
+            expect(result.blocks[0].to).toBe(blocks[0].to);
+          });
+        });
       });
 
       describe('current', () => {
@@ -777,6 +794,25 @@ describe('expandUniqueDateBlocks', () => {
             });
           });
         });
+
+        describe('with larger first followed by smaller', () => {
+          it('should start with the new value and end with the former value.', () => {
+            const blocks = [
+              { i: 0, to: 5, value: 'a' },
+              { i: 0, value: 'b' }
+            ];
+            const result = overwriteNextExpand(blocks);
+
+            expect(result.blocks.length).toBe(2);
+            expect(result.discarded.length).toBe(0);
+            expect(result.blocks[0].value).toBe(blocks[1].value);
+            expect(result.blocks[1].value).toBe(blocks[0].value);
+            expect(result.blocks[0].i).toBe(blocks[1].i);
+            expect(result.blocks[0].to).toBe(blocks[1].to ?? 0);
+            expect(result.blocks[1].i).toBe(blocks[1].i + 1);
+            expect(result.blocks[1].to).toBe(blocks[0].to);
+          });
+        });
       });
     });
 
@@ -968,5 +1004,81 @@ describe('expandUniqueDateBlocks', () => {
         });
       });
     });
+
+    describe('scenarios', () => {
+      it('should expand the blocks and not infinitely loop if another block comes after that has a 0-0 range.', async () => {
+        const i = 0;
+        const to = 2;
+
+        const allBlocks: any[] = [
+          {
+            i: 0,
+            to: 2
+          },
+          { i: 0, to: undefined }
+        ];
+
+        const requestedRangeBlocks = expandUniqueDateBlocks({
+          startAtIndex: i,
+          endAtIndex: to,
+          fillOption: 'fill',
+          overwriteOption: 'current',
+          fillFactory: (x) => x
+        })(allBlocks);
+
+        expect(requestedRangeBlocks.blocks).toBeDefined();
+        expect(requestedRangeBlocks.blocks.length).toBe(2);
+        expect(requestedRangeBlocks.blocks[0].i).toBe(0);
+        expect(requestedRangeBlocks.blocks[0].to).toBe(0);
+        expect(requestedRangeBlocks.blocks[1].i).toBe(1);
+        expect(requestedRangeBlocks.blocks[1].to).toBe(2);
+      });
+    });
+  });
+});
+
+describe('sortDateBlockRanges', () => {
+  it('should retain the order for items that have the same start index.', () => {
+    const allBlocks = [
+      {
+        i: 0,
+        to: 2,
+        id: 'a'
+      },
+      { i: 0, to: undefined, id: 'b' },
+      { i: 0, to: 3, id: 'c' },
+      { i: 0, to: 1, id: 'd' },
+      { i: 0, to: 100, id: 'e' }
+    ];
+
+    const sorted = sortDateBlockRanges(allBlocks);
+
+    expect(sorted[0].id).toBe('a');
+    expect(sorted[1].id).toBe('b');
+    expect(sorted[2].id).toBe('c');
+    expect(sorted[3].id).toBe('d');
+    expect(sorted[4].id).toBe('e');
+  });
+
+  it('should retain the before/after order for items that have the same start index.', () => {
+    const allBlocks = [
+      {
+        i: 0,
+        to: 2,
+        id: 'a'
+      },
+      { i: 1, to: undefined, id: 'b' },
+      { i: 2, to: 3, id: 'c' },
+      { i: 3, to: 1, id: 'd' },
+      { i: 0, to: 100, id: 'e' }
+    ];
+
+    const sorted = sortDateBlockRanges(allBlocks);
+
+    expect(sorted[0].id).toBe('a');
+    expect(sorted[1].id).toBe('e');
+    expect(sorted[2].id).toBe('b');
+    expect(sorted[3].id).toBe('c');
+    expect(sorted[4].id).toBe('d');
   });
 });

packages/date/src/lib/date/date.block.ts

@@ -1,4 +1,4 @@
-import { DayOfWeek, RequiredOnKeys, IndexNumber, IndexRange, indexRangeCheckFunction, IndexRef, MINUTES_IN_DAY, MS_IN_DAY, sortAscendingIndexNumberRefFunction, UniqueModel, lastValue, FactoryWithRequiredInput, FilterFunction, mergeFilterFunctions, range, Milliseconds, Hours, MapFunction, getNextDay } from '@dereekb/util';
+import { DayOfWeek, RequiredOnKeys, IndexNumber, IndexRange, indexRangeCheckFunction, IndexRef, MINUTES_IN_DAY, MS_IN_DAY, UniqueModel, lastValue, FactoryWithRequiredInput, FilterFunction, mergeFilterFunctions, range, Milliseconds, Hours, MapFunction, getNextDay, SortCompareFunction, sortAscendingIndexNumberRefFunction } from '@dereekb/util';
 import { dateRange, DateRange, DateRangeDayDistanceInput, DateRangeType, isDateRange } from './date.range';
 import { DateDurationSpan } from './date.duration';
 import { differenceInDays, differenceInMilliseconds, isBefore, addDays, addMinutes, setSeconds, addMilliseconds, hoursToMilliseconds, addHours } from 'date-fns';
@@ -451,6 +451,27 @@ export function dateBlockRange(i: number, to?: number): DateBlockRangeWithRange
   return { i, to: to ?? i };
 }
 
+/**
+ * Sorts the input ranges by index and distance (to values).
+ *
+ * In many cases sortAscendingIndexNumberRefFunction may be preferential since
+ *
+ * @returns
+ */
+export function sortDateBlockRangeAndSizeFunction<T extends DateBlockRange>(): SortCompareFunction<T> {
+  return (a, b) => a.i - b.i || (a.to ?? a.i) - (b.to ?? b.i);
+}
+
+/**
+ * Sorts the input date ranges. This will retain the before/after order while also sorting items by index.
+ *
+ * @param input
+ * @returns
+ */
+export function sortDateBlockRanges<T extends DateBlockRange>(input: T[]): T[] {
+  return input.sort(sortAscendingIndexNumberRefFunction());
+}
+
 /**
  * DateBlockRange that is known to have a to value.
  */
@@ -467,7 +488,7 @@ export function groupToDateBlockRanges(input: (DateBlock | DateBlockRange)[]): D
   }
 
   // sort by index in ascending order
-  const blocks = input.sort(sortAscendingIndexNumberRefFunction());
+  const blocks = sortDateBlockRanges(input);
 
   function newBlockFromBlocksIndex(blocksIndex: number): DateBlockRangeWithRange {
     const { i, to } = blocks[blocksIndex] as DateBlockRange;
@@ -553,10 +574,10 @@ export interface UniqueDateBlockRangeGroup<B extends DateBlockRange | UniqueDate
 }
 
 /**
- * Groups all input DateBlockRange or UniqueDateBlock values into a UniqueDateBlockRangeGroup value.
+ * Groups all input DateBlockRange or UniqueDateBlock values into a UniqueDateBlockRangeGroup value amd sorts the input.
  */
 export function groupUniqueDateBlocks<B extends DateBlockRange | UniqueDateBlock>(input: B[]): UniqueDateBlockRangeGroup<B> {
-  const blocks = [...input].sort(sortAscendingIndexNumberRefFunction());
+  const blocks = sortDateBlockRanges([...input]);
 
   const i = 0;
   let to: number;
@@ -662,7 +683,7 @@ export function expandUniqueDateBlocks<B extends DateBlockRange | UniqueDateBloc
         addGapBlock(gapStartIndex, i - 1);
       }
 
-      const to = Math.min(inputTo, maxAllowedIndex);
+      const to = Math.min(inputTo, maxAllowedIndex) || 0;
 
       const block: B = {
         ...inputBlock,
@@ -694,7 +715,7 @@ export function expandUniqueDateBlocks<B extends DateBlockRange | UniqueDateBloc
         };
 
         const block: B = fillFactory(dateBlockRange);
-        addBlockWithRange(block, i, to);
+        addBlockWithRange(block, i, to ?? i);
       } else if (blocks.length > 0) {
         // do not extend if no blocks have been pushed.
         const blockToExtend = lastValue(blocks);
@@ -776,6 +797,19 @@ export function expandUniqueDateBlocks<B extends DateBlockRange | UniqueDateBloc
           addBlockWithRange(current, currentNextIndex, currentEndIndex);
           // change next to start at the next range
           continueToNext({ ...next, i: currentEndIndex + 1, to: nextEndIndex });
+        } else {
+          // the next item ends before the current item.
+          if (overwriteOption === 'current') {
+            // add the next item first since it overwrites the current
+            addBlockWithRange(next, nextStartIndex, nextEndIndex);
+            // continue with the current item as next.
+            continueToNext({ ...current, i: nextEndIndex + 1, to: currentEndIndex });
+          } else {
+            // discard the next value.
+            discard(next);
+            // continue with the current value
+            continueToNext(current);
+          }
         }
       } else {
         // Check for any overlap
@@ -796,7 +830,6 @@ export function expandUniqueDateBlocks<B extends DateBlockRange | UniqueDateBloc
         } else {
           // add the block
           addBlockWithRange(current, currentNextIndex, currentEndIndex);
-
           // continue to next
           continueToNext();
         }
@@ -805,7 +838,6 @@ export function expandUniqueDateBlocks<B extends DateBlockRange | UniqueDateBloc
 
     if (current != null) {
       // if current != null, then atleast one block was input/remaining.
-
       const lastStartIndex = current.i;
       const lastEndIndex = dateBlockEndIndex(current);