Fix bug with memoized binary search's found state, part 2

Fixes #4
jridgewell · Apr 20, 2022 · 589574e · 589574e
1 parent bcbd2de
commit 589574e
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Showing 2 changed files with 13 additions and 6 deletions.
diff --git a/src/binary-search.ts b/src/binary-search.ts
@@ -97,7 +97,7 @@ export function memoizedBinarySearch(
   let high = haystack.length - 1;
   if (key === lastKey) {
     if (needle === lastNeedle) {
-      found = haystack[lastIndex][COLUMN] === needle;
+      found = lastIndex !== -1 && haystack[lastIndex][COLUMN] === needle;
       return lastIndex;
     }
 

diff --git a/test/binary-search.test.ts b/test/binary-search.test.ts
@@ -378,7 +378,7 @@ describe('binary search', () => {
 });
 
 describe('memoizedBinarySearch', () => {
-  const array: SourceMapSegment[] = [[0], [5], [10]];
+  const array: SourceMapSegment[] = [[1], [5], [10]];
 
   test('refinds same index', (t) => {
     const memo = memoizedState();
@@ -388,12 +388,19 @@ describe('memoizedBinarySearch', () => {
   });
 
   test('restores found state', (t) => {
-    const memo = memoizedState();
+    const memo1 = memoizedState();
+    const memo2 = memoizedState();
 
-    t.is(memoizedBinarySearch(array, 6, memo, 0), 1);
-    binarySearch(array, 0, 0, array.length - 1);
+    t.is(memoizedBinarySearch(array, 0, memo1, 0), -1);
+    t.is(found, false);
+
+    t.is(memoizedBinarySearch(array, 5, memo2, 0), 1);
     t.is(found, true);
-    t.is(memoizedBinarySearch(array, 6, memo, 0), 1);
+
+    t.is(memoizedBinarySearch(array, 0, memo1, 0), -1);
     t.is(found, false);
+
+    t.is(memoizedBinarySearch(array, 5, memo2, 0), 1);
+    t.is(found, true);
   });
 });