// META: global=window,worker,shadowrealm
// META: script=../resources/test-utils.js
// META: script=../resources/rs-utils.js
'use strict';
test(() => {
new TransformStream({ transform() { } });
}, 'TransformStream can be constructed with a transform function');
test(() => {
new TransformStream();
new TransformStream({});
}, 'TransformStream can be constructed with no transform function');
test(() => {
const ts = new TransformStream({ transform() { } });
const writer = ts.writable.getWriter();
assert_equals(writer.desiredSize, 1, 'writer.desiredSize should be 1');
}, 'TransformStream writable starts in the writable state');
promise_test(() => {
const ts = new TransformStream();
const writer = ts.writable.getWriter();
writer.write('a');
assert_equals(writer.desiredSize, 0, 'writer.desiredSize should be 0 after write()');
return ts.readable.getReader().read().then(result => {
assert_equals(result.value, 'a',
'result from reading the readable is the same as was written to writable');
assert_false(result.done, 'stream should not be done');
return delay(0).then(() => assert_equals(writer.desiredSize, 1, 'desiredSize should be 1 again'));
});
}, 'Identity TransformStream: can read from readable what is put into writable');
promise_test(() => {
let c;
const ts = new TransformStream({
start(controller) {
c = controller;
},
transform(chunk) {
c.enqueue(chunk.toUpperCase());
}
});
const writer = ts.writable.getWriter();
writer.write('a');
return ts.readable.getReader().read().then(result => {
assert_equals(result.value, 'A',
'result from reading the readable is the transformation of what was written to writable');
assert_false(result.done, 'stream should not be done');
});
}, 'Uppercaser sync TransformStream: can read from readable transformed version of what is put into writable');
promise_test(() => {
let c;
const ts = new TransformStream({
start(controller) {
c = controller;
},
transform(chunk) {
c.enqueue(chunk.toUpperCase());
c.enqueue(chunk.toUpperCase());
}
});
const writer = ts.writable.getWriter();
writer.write('a');
const reader = ts.readable.getReader();
return reader.read().then(result1 => {
assert_equals(result1.value, 'A',
'the first chunk read is the transformation of the single chunk written');
assert_false(result1.done, 'stream should not be done');
return reader.read().then(result2 => {
assert_equals(result2.value, 'A',
'the second chunk read is also the transformation of the single chunk written');
assert_false(result2.done, 'stream should not be done');
});
});
}, 'Uppercaser-doubler sync TransformStream: can read both chunks put into the readable');
promise_test(() => {
let c;
const ts = new TransformStream({
start(controller) {
c = controller;
},
transform(chunk) {
return delay(0).then(() => c.enqueue(chunk.toUpperCase()));
}
});
const writer = ts.writable.getWriter();
writer.write('a');
return ts.readable.getReader().read().then(result => {
assert_equals(result.value, 'A',
'result from reading the readable is the transformation of what was written to writable');
assert_false(result.done, 'stream should not be done');
});
}, 'Uppercaser async TransformStream: can read from readable transformed version of what is put into writable');
promise_test(() => {
let doSecondEnqueue;
let returnFromTransform;
const ts = new TransformStream({
transform(chunk, controller) {
delay(0).then(() => controller.enqueue(chunk.toUpperCase()));
doSecondEnqueue = () => controller.enqueue(chunk.toUpperCase());
return new Promise(resolve => {
returnFromTransform = resolve;
});
}
});
const reader = ts.readable.getReader();
const writer = ts.writable.getWriter();
writer.write('a');
return reader.read().then(result1 => {
assert_equals(result1.value, 'A',
'the first chunk read is the transformation of the single chunk written');
assert_false(result1.done, 'stream should not be done');
doSecondEnqueue();
return reader.read().then(result2 => {
assert_equals(result2.value, 'A',
'the second chunk read is also the transformation of the single chunk written');
assert_false(result2.done, 'stream should not be done');
returnFromTransform();
});
});
}, 'Uppercaser-doubler async TransformStream: can read both chunks put into the readable');
promise_test(() => {
const ts = new TransformStream({ transform() { } });
const writer = ts.writable.getWriter();
writer.close();
return Promise.all([writer.closed, ts.readable.getReader().closed]);
}, 'TransformStream: by default, closing the writable closes the readable (when there are no queued writes)');
promise_test(() => {
let transformResolve;
const transformPromise = new Promise(resolve => {
transformResolve = resolve;
});
const ts = new TransformStream({
transform() {
return transformPromise;
}
}, undefined, { highWaterMark: 1 });
const writer = ts.writable.getWriter();
writer.write('a');
writer.close();
let rsClosed = false;
ts.readable.getReader().closed.then(() => {
rsClosed = true;
});
return delay(0).then(() => {
assert_equals(rsClosed, false, 'readable is not closed after a tick');
transformResolve();
return writer.closed.then(() => {
// TODO: Is this expectation correct?
assert_equals(rsClosed, true, 'readable is closed at that point');
});
});
}, 'TransformStream: by default, closing the writable waits for transforms to finish before closing both');
promise_test(() => {
let c;
const ts = new TransformStream({
start(controller) {
c = controller;
},
transform() {
c.enqueue('x');
c.enqueue('y');
return delay(0);
}
});
const writer = ts.writable.getWriter();
writer.write('a');
writer.close();
const readableChunks = readableStreamToArray(ts.readable);
return writer.closed.then(() => {
return readableChunks.then(chunks => {
assert_array_equals(chunks, ['x', 'y'], 'both enqueued chunks can be read from the readable');
});
});
}, 'TransformStream: by default, closing the writable closes the readable after sync enqueues and async done');
promise_test(() => {
let c;
const ts = new TransformStream({
start(controller) {
c = controller;
},
transform() {
return delay(0)
.then(() => c.enqueue('x'))
.then(() => c.enqueue('y'))
.then(() => delay(0));
}
});
const writer = ts.writable.getWriter();
writer.write('a');
writer.close();
const readableChunks = readableStreamToArray(ts.readable);
return writer.closed.then(() => {
return readableChunks.then(chunks => {
assert_array_equals(chunks, ['x', 'y'], 'both enqueued chunks can be read from the readable');
});
});
}, 'TransformStream: by default, closing the writable closes the readable after async enqueues and async done');
promise_test(() => {
let c;
const ts = new TransformStream({
suffix: '-suffix',
start(controller) {
c = controller;
c.enqueue('start' + this.suffix);
},
transform(chunk) {
c.enqueue(chunk + this.suffix);
},
flush() {
c.enqueue('flushed' + this.suffix);
}
});
const writer = ts.writable.getWriter();
writer.write('a');
writer.close();
const readableChunks = readableStreamToArray(ts.readable);
return writer.closed.then(() => {
return readableChunks.then(chunks => {
assert_array_equals(chunks, ['start-suffix', 'a-suffix', 'flushed-suffix'], 'all enqueued chunks have suffixes');
});
});
}, 'Transform stream should call transformer methods as methods');
promise_test(() => {
function functionWithOverloads() {}
functionWithOverloads.apply = () => assert_unreached('apply() should not be called');
functionWithOverloads.call = () => assert_unreached('call() should not be called');
const ts = new TransformStream({
start: functionWithOverloads,
transform: functionWithOverloads,
flush: functionWithOverloads
});
const writer = ts.writable.getWriter();
writer.write('a');
writer.close();
return readableStreamToArray(ts.readable);
}, 'methods should not not have .apply() or .call() called');
promise_test(t => {
let startCalled = false;
let startDone = false;
let transformDone = false;
let flushDone = false;
const ts = new TransformStream({
start() {
startCalled = true;
return flushAsyncEvents().then(() => {
startDone = true;
});
},
transform() {
return t.step(() => {
assert_true(startDone, 'transform() should not be called until the promise returned from start() has resolved');
return flushAsyncEvents().then(() => {
transformDone = true;
});
});
},
flush() {
return t.step(() => {
assert_true(transformDone,
'flush() should not be called until the promise returned from transform() has resolved');
return flushAsyncEvents().then(() => {
flushDone = true;
});
});
}
}, undefined, { highWaterMark: 1 });
assert_true(startCalled, 'start() should be called synchronously');
const writer = ts.writable.getWriter();
const writePromise = writer.write('a');
return writer.close().then(() => {
assert_true(flushDone, 'promise returned from flush() should have resolved');
return writePromise;
});
}, 'TransformStream start, transform, and flush should be strictly ordered');
promise_test(() => {
let transformCalled = false;
const ts = new TransformStream({
transform() {
transformCalled = true;
}
}, undefined, { highWaterMark: Infinity });
// transform() is only called synchronously when there is no backpressure and all microtasks have run.
return delay(0).then(() => {
const writePromise = ts.writable.getWriter().write();
assert_true(transformCalled, 'transform() should have been called');
return writePromise;
});
}, 'it should be possible to call transform() synchronously');
promise_test(() => {
const ts = new TransformStream({}, undefined, { highWaterMark: 0 });
const writer = ts.writable.getWriter();
writer.close();
return Promise.all([writer.closed, ts.readable.getReader().closed]);
}, 'closing the writable should close the readable when there are no queued chunks, even with backpressure');
test(() => {
new TransformStream({
start(controller) {
controller.terminate();
assert_throws_js(TypeError, () => controller.enqueue(), 'enqueue should throw');
}
});
}, 'enqueue() should throw after controller.terminate()');
promise_test(() => {
let controller;
const ts = new TransformStream({
start(c) {
controller = c;
}
});
const cancelPromise = ts.readable.cancel();
assert_throws_js(TypeError, () => controller.enqueue(), 'enqueue should throw');
return cancelPromise;
}, 'enqueue() should throw after readable.cancel()');
test(() => {
new TransformStream({
start(controller) {
controller.terminate();
controller.terminate();
}
});
}, 'controller.terminate() should do nothing the second time it is called');
promise_test(t => {
let controller;
const ts = new TransformStream({
start(c) {
controller = c;
}
});
const cancelReason = { name: 'cancelReason' };
const cancelPromise = ts.readable.cancel(cancelReason);
controller.terminate();
return Promise.all([
cancelPromise,
promise_rejects_js(t, TypeError, ts.writable.getWriter().closed, 'closed should reject with TypeError')
]);
}, 'terminate() should abort writable immediately after readable.cancel()');
promise_test(t => {
let controller;
const ts = new TransformStream({
start(c) {
controller = c;
}
});
const cancelReason = { name: 'cancelReason' };
return ts.readable.cancel(cancelReason).then(() => {
controller.terminate();
return promise_rejects_exactly(t, cancelReason, ts.writable.getWriter().closed, 'closed should reject with TypeError');
})
}, 'terminate() should do nothing after readable.cancel() resolves');
promise_test(() => {
let calls = 0;
new TransformStream({
start() {
++calls;
}
});
return flushAsyncEvents().then(() => {
assert_equals(calls, 1, 'start() should have been called exactly once');
});
}, 'start() should not be called twice');
test(() => {
assert_throws_js(RangeError, () => new TransformStream({ readableType: 'bytes' }), 'constructor should throw');
}, 'specifying a defined readableType should throw');
test(() => {
assert_throws_js(RangeError, () => new TransformStream({ writableType: 'bytes' }), 'constructor should throw');
}, 'specifying a defined writableType should throw');
test(() => {
class Subclass extends TransformStream {
extraFunction() {
return true;
}
}
assert_equals(
Object.getPrototypeOf(Subclass.prototype), TransformStream.prototype,
'Subclass.prototype\'s prototype should be TransformStream.prototype');
assert_equals(Object.getPrototypeOf(Subclass), TransformStream,
'Subclass\'s prototype should be TransformStream');
const sub = new Subclass();
assert_true(sub instanceof TransformStream,
'Subclass object should be an instance of TransformStream');
assert_true(sub instanceof Subclass,
'Subclass object should be an instance of Subclass');
const readableGetter = Object.getOwnPropertyDescriptor(
TransformStream.prototype, 'readable').get;
assert_equals(readableGetter.call(sub), sub.readable,
'Subclass object should pass brand check');
assert_true(sub.extraFunction(),
'extraFunction() should be present on Subclass object');
}, 'Subclassing TransformStream should work');
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