1 files changed, 78 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/TypedArray/prototype/reduce/callbackfn-resize.js b/js/src/tests/test262/built-ins/TypedArray/prototype/reduce/callbackfn-resize.js
new file mode 100644
index 0000000000..a10f3adf0b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/TypedArray/prototype/reduce/callbackfn-resize.js
@@ -0,0 +1,78 @@
+// |reftest| skip -- resizable-arraybuffer is not supported
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.reduce
+description: Instance buffer can be resized during iteration
+includes: [testTypedArray.js, compareArray.js]
+features: [TypedArray, resizable-arraybuffer]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  var BPE = TA.BYTES_PER_ELEMENT;
+  var buffer = new ArrayBuffer(BPE * 3, {maxByteLength: BPE * 3});
+  var sample = new TA(buffer);
+  var finalNext, expectedPrevs, expectedNexts, expectedIndices, expectedArrays;
+  var prevs, nexts, indices, arrays, result;
+
+  prevs = [];
+  nexts = [];
+  indices = [];
+  arrays = [];
+  result = sample.reduce(function(prev, next, index, array) {
+    if (prevs.length === 0) {
+      try {
+        buffer.resize(2 * BPE);
+        finalNext = undefined;
+        expectedPrevs = [262, 0];
+        expectedNexts = [0, 0];
+        expectedIndices = [0, 1];
+        expectedArrays = [sample, sample];
+      } catch (_) {
+        finalNext = 0;
+        expectedPrevs = [262, 0, 1];
+        expectedNexts = [0, 0, 0];
+        expectedIndices = [0, 1, 2];
+        expectedArrays = [sample, sample, sample];
+      }
+    }
+
+    prevs.push(prev);
+    nexts.push(next);
+    indices.push(index);
+    arrays.push(array);
+    return index;
+  }, 262);
+
+  assert.compareArray(prevs, [262, 0, 1], 'prevs (shrink)');
+  assert.compareArray(nexts, [0, 0, finalNext], 'nexts (shrink)');
+  assert.compareArray(indices, [0, 1, 2], 'indices (shrink)');
+  assert.compareArray(arrays, [sample, sample, sample], 'arrays (shrink)');
+  assert.sameValue(result, 2, 'result (shrink)');
+
+  prevs = [];
+  nexts = [];
+  indices = [];
+  arrays = [];
+  result = sample.reduce(function(prev, next, index, array) {
+    if (prevs.length === 0) {
+      try {
+        buffer.resize(3 * BPE);
+      } catch (_) {}
+    }
+
+    prevs.push(prev);
+    nexts.push(next);
+    indices.push(index);
+    arrays.push(array);
+    return index;
+  }, 262);
+
+  assert.compareArray(prevs, expectedPrevs, 'prevs (grow)');
+  assert.compareArray(nexts, expectedNexts, 'nexts (grow)');
+  assert.compareArray(indices, expectedIndices, 'indices (grow)');
+  assert.compareArray(arrays, expectedArrays, 'arrays (grow)');
+  assert.sameValue(result, expectedIndices[expectedIndices.length - 1], 'result (grow)');
+});
+
+reportCompare(0, 0);