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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /streams/transferable/transform-stream.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta charset="utf-8">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../resources/test-utils.js"></script>
<script>
'use strict';
promise_test(t => {
const orig = new TransformStream();
const promise = new Promise(resolve => {
addEventListener('message', t.step_func(evt => {
const transferred = evt.data;
assert_equals(transferred.constructor, TransformStream,
'transferred should be a TransformStream in this realm');
assert_true(transferred instanceof TransformStream,
'instanceof check should pass');
// Perform a brand-check on |transferred|.
const readableGetter = Object.getOwnPropertyDescriptor(
TransformStream.prototype, 'readable').get;
assert_true(readableGetter.call(transferred) instanceof ReadableStream,
'brand check should pass and readable stream should result');
const writableGetter = Object.getOwnPropertyDescriptor(
TransformStream.prototype, 'writable').get;
assert_true(writableGetter.call(transferred) instanceof WritableStream,
'brand check should pass and writable stream should result');
resolve();
}), {once: true});
});
postMessage(orig, '*', [orig]);
assert_true(orig.readable.locked, 'the readable side should be locked');
assert_true(orig.writable.locked, 'the writable side should be locked');
return promise;
}, 'window.postMessage should be able to transfer a TransformStream');
test(() => {
const ts = new TransformStream();
const writer = ts.writable.getWriter();
assert_throws_dom('DataCloneError', () => postMessage(ts, '*', [ts]),
'postMessage should throw');
assert_false(ts.readable.locked, 'readable side should not get locked');
}, 'a TransformStream with a locked writable should not be transferable');
test(() => {
const ts = new TransformStream();
const reader = ts.readable.getReader();
assert_throws_dom('DataCloneError', () => postMessage(ts, '*', [ts]),
'postMessage should throw');
assert_false(ts.writable.locked, 'writable side should not get locked');
}, 'a TransformStream with a locked readable should not be transferable');
test(() => {
const ts = new TransformStream();
const reader = ts.readable.getReader();
const writer = ts.writable.getWriter();
assert_throws_dom('DataCloneError', () => postMessage(ts, '*', [ts]),
'postMessage should throw');
}, 'a TransformStream with both sides locked should not be transferable');
promise_test(t => {
const source = new ReadableStream({
start(controller) {
controller.enqueue('hello ');
controller.enqueue('there ');
controller.close();
}
});
let resolve;
const ready = new Promise(r => resolve = r);
let result = '';
const sink = new WritableStream({
write(chunk) {
if (result) {
resolve();
}
result += chunk;
}
});
const transform1 = new TransformStream({
transform(chunk, controller) {
controller.enqueue(chunk.toUpperCase());
}
});
const transform2 = new TransformStream({
transform(chunk, controller) {
controller.enqueue(chunk + chunk);
}
});
const promise = new Promise(resolve => {
addEventListener('message', t.step_func(evt => {
const data = evt.data;
resolve(data.source
.pipeThrough(data.transform1)
.pipeThrough(data.transform2)
.pipeTo(data.sink));
}));
});
postMessage({source, sink, transform1, transform2}, '*',
[source, transform1, sink, transform2]);
return ready
.then(() => {
assert_equals(result, 'HELLO HELLO THERE THERE ',
'transforms should have been applied');
});
}, 'piping through transferred transforms should work');
</script>