| <!DOCTYPE html> |
| <script src='../resources/testharness.js'></script> |
| <script src='../resources/testharnessreport.js'></script> |
| <script> |
| |
| promise_test(async () => { |
| add_completion_callback(() => delete Object.prototype.then); |
| let thenCounter = 0; |
| Object.prototype.then = (onFulfilled) => { |
| ++thenCounter; |
| onFulfilled({ then : null }); |
| }; |
| |
| const a = new ReadableStream({ |
| start: (c) => { |
| c.enqueue(new Uint8Array([0])); |
| c.enqueue(new Uint8Array([1])); |
| c.close(); |
| }, |
| type: "bytes" |
| }); |
| |
| const [b, c] = a.tee(); |
| |
| const reader = b.getReader(); |
| |
| await reader.read(); |
| |
| assert_equals(thenCounter, 1); |
| }, "Object.prototype.then should not allow observing the tee algorithm") |
| </script> |
