// META: global=window,worker,shadowrealm
// META: script=../resources/rs-utils.js
// META: script=../resources/test-utils.js
// META: script=../resources/recording-streams.js
// META: script=../resources/rs-test-templates.js
'use strict';
test(() => {
const rs = new ReadableStream();
const result = rs.tee();
assert_true(Array.isArray(result), 'return value should be an array');
assert_equals(result.length, 2, 'array should have length 2');
assert_equals(result[0].constructor, ReadableStream, '0th element should be a ReadableStream');
assert_equals(result[1].constructor, ReadableStream, '1st element should be a ReadableStream');
}, 'ReadableStream teeing: rs.tee() returns an array of two ReadableStreams');
promise_test(t => {
const rs = new ReadableStream({
start(c) {
c.enqueue('a');
c.enqueue('b');
c.close();
}
});
const branch = rs.tee();
const branch1 = branch[0];
const branch2 = branch[1];
const reader1 = branch1.getReader();
const reader2 = branch2.getReader();
reader2.closed.then(t.unreached_func('branch2 should not be closed'));
return Promise.all([
reader1.closed,
reader1.read().then(r => {
assert_object_equals(r, { value: 'a', done: false }, 'first chunk from branch1 should be correct');
}),
reader1.read().then(r => {
assert_object_equals(r, { value: 'b', done: false }, 'second chunk from branch1 should be correct');
}),
reader1.read().then(r => {
assert_object_equals(r, { value: undefined, done: true }, 'third read() from branch1 should be done');
}),
reader2.read().then(r => {
assert_object_equals(r, { value: 'a', done: false }, 'first chunk from branch2 should be correct');
})
]);
}, 'ReadableStream teeing: should be able to read one branch to the end without affecting the other');
promise_test(() => {
const theObject = { the: 'test object' };
const rs = new ReadableStream({
start(c) {
c.enqueue(theObject);
}
});
const branch = rs.tee();
const branch1 = branch[0];
const branch2 = branch[1];
const reader1 = branch1.getReader();
const reader2 = branch2.getReader();
return Promise.all([reader1.read(), reader2.read()]).then(values => {
assert_object_equals(values[0], values[1], 'the values should be equal');
});
}, 'ReadableStream teeing: values should be equal across each branch');
promise_test(t => {
const theError = { name: 'boo!' };
const rs = new ReadableStream({
start(c) {
c.enqueue('a');
c.enqueue('b');
},
pull() {
throw theError;
}
});
const branches = rs.tee();
const reader1 = branches[0].getReader();
const reader2 = branches[1].getReader();
reader1.label = 'reader1';
reader2.label = 'reader2';
return Promise.all([
promise_rejects_exactly(t, theError, reader1.closed),
promise_rejects_exactly(t, theError, reader2.closed),
reader1.read().then(r => {
assert_object_equals(r, { value: 'a', done: false }, 'should be able to read the first chunk in branch1');
}),
reader1.read().then(r => {
assert_object_equals(r, { value: 'b', done: false }, 'should be able to read the second chunk in branch1');
return promise_rejects_exactly(t, theError, reader2.read());
})
.then(() => promise_rejects_exactly(t, theError, reader1.read()))
]);
}, 'ReadableStream teeing: errors in the source should propagate to both branches');
promise_test(() => {
const rs = new ReadableStream({
start(c) {
c.enqueue('a');
c.enqueue('b');
c.close();
}
});
const branches = rs.tee();
const branch1 = branches[0];
const branch2 = branches[1];
branch1.cancel();
return Promise.all([
readableStreamToArray(branch1).then(chunks => {
assert_array_equals(chunks, [], 'branch1 should have no chunks');
}),
readableStreamToArray(branch2).then(chunks => {
assert_array_equals(chunks, ['a', 'b'], 'branch2 should have two chunks');
})
]);
}, 'ReadableStream teeing: canceling branch1 should not impact branch2');
promise_test(() => {
const rs = new ReadableStream({
start(c) {
c.enqueue('a');
c.enqueue('b');
c.close();
}
});
const branches = rs.tee();
const branch1 = branches[0];
const branch2 = branches[1];
branch2.cancel();
return Promise.all([
readableStreamToArray(branch1).then(chunks => {
assert_array_equals(chunks, ['a', 'b'], 'branch1 should have two chunks');
}),
readableStreamToArray(branch2).then(chunks => {
assert_array_equals(chunks, [], 'branch2 should have no chunks');
})
]);
}, 'ReadableStream teeing: canceling branch2 should not impact branch1');
templatedRSTeeCancel('ReadableStream teeing', (extras) => {
return new ReadableStream({ ...extras });
});
promise_test(t => {
let controller;
const stream = new ReadableStream({ start(c) { controller = c; } });
const [branch1, branch2] = stream.tee();
const error = new Error();
error.name = 'distinctive';
// Ensure neither branch is waiting in ReadableStreamDefaultReaderRead().
controller.enqueue();
controller.enqueue();
return delay(0).then(() => {
// This error will have to be detected via [[closedPromise]].
controller.error(error);
const reader1 = branch1.getReader();
const reader2 = branch2.getReader();
return Promise.all([
promise_rejects_exactly(t, error, reader1.closed, 'reader1.closed should reject'),
promise_rejects_exactly(t, error, reader2.closed, 'reader2.closed should reject')
]);
});
}, 'ReadableStream teeing: erroring a teed stream should error both branches');
promise_test(() => {
let controller;
const rs = new ReadableStream({
start(c) {
controller = c;
}
});
const branches = rs.tee();
const reader1 = branches[0].getReader();
const reader2 = branches[1].getReader();
const promise = Promise.all([reader1.closed, reader2.closed]);
controller.close();
return promise;
}, 'ReadableStream teeing: closing the original should immediately close the branches');
promise_test(t => {
let controller;
const rs = new ReadableStream({
start(c) {
controller = c;
}
});
const branches = rs.tee();
const reader1 = branches[0].getReader();
const reader2 = branches[1].getReader();
const theError = { name: 'boo!' };
const promise = Promise.all([
promise_rejects_exactly(t, theError, reader1.closed),
promise_rejects_exactly(t, theError, reader2.closed)
]);
controller.error(theError);
return promise;
}, 'ReadableStream teeing: erroring the original should immediately error the branches');
promise_test(async t => {
let controller;
const rs = new ReadableStream({
start(c) {
controller = c;
}
});
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
const cancelPromise = reader2.cancel();
controller.enqueue('a');
const read1 = await reader1.read();
assert_object_equals(read1, { value: 'a', done: false }, 'first read() from branch1 should fulfill with the chunk');
controller.close();
const read2 = await reader1.read();
assert_object_equals(read2, { value: undefined, done: true }, 'second read() from branch1 should be done');
await Promise.all([
reader1.closed,
cancelPromise
]);
}, 'ReadableStream teeing: canceling branch1 should finish when branch2 reads until end of stream');
promise_test(async t => {
let controller;
const theError = { name: 'boo!' };
const rs = new ReadableStream({
start(c) {
controller = c;
}
});
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
const cancelPromise = reader2.cancel();
controller.error(theError);
await Promise.all([
promise_rejects_exactly(t, theError, reader1.read()),
cancelPromise
]);
}, 'ReadableStream teeing: canceling branch1 should finish when original stream errors');
promise_test(async () => {
const rs = new ReadableStream({});
const [branch1, branch2] = rs.tee();
const cancel1 = branch1.cancel();
await flushAsyncEvents();
const cancel2 = branch2.cancel();
await Promise.all([cancel1, cancel2]);
}, 'ReadableStream teeing: canceling both branches in sequence with delay');
promise_test(async t => {
const theError = { name: 'boo!' };
const rs = new ReadableStream({
cancel() {
throw theError;
}
});
const [branch1, branch2] = rs.tee();
const cancel1 = branch1.cancel();
await flushAsyncEvents();
const cancel2 = branch2.cancel();
await Promise.all([
promise_rejects_exactly(t, theError, cancel1),
promise_rejects_exactly(t, theError, cancel2)
]);
}, 'ReadableStream teeing: failing to cancel when canceling both branches in sequence with delay');
test(t => {
// Copy original global.
const oldReadableStream = ReadableStream;
const getReader = ReadableStream.prototype.getReader;
const origRS = new ReadableStream();
// Replace the global ReadableStream constructor with one that doesn't work.
ReadableStream = function() {
throw new Error('global ReadableStream constructor called');
};
t.add_cleanup(() => {
ReadableStream = oldReadableStream;
});
// This will probably fail if the global ReadableStream constructor was used.
const [rs1, rs2] = origRS.tee();
// These will definitely fail if the global ReadableStream constructor was used.
assert_not_equals(getReader.call(rs1), undefined, 'getReader should work on rs1');
assert_not_equals(getReader.call(rs2), undefined, 'getReader should work on rs2');
}, 'ReadableStreamTee should not use a modified ReadableStream constructor from the global object');
promise_test(t => {
const rs = recordingReadableStream({}, { highWaterMark: 0 });
// Create two branches, each with a HWM of 1. This should result in one
// chunk being pulled, not two.
rs.tee();
return flushAsyncEvents().then(() => {
assert_array_equals(rs.events, ['pull'], 'pull should only be called once');
});
}, 'ReadableStreamTee should not pull more chunks than can fit in the branch queue');
promise_test(t => {
const rs = recordingReadableStream({
pull(controller) {
controller.enqueue('a');
}
}, { highWaterMark: 0 });
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
return Promise.all([reader1.read(), reader2.read()])
.then(() => {
assert_array_equals(rs.events, ['pull', 'pull'], 'pull should be called twice');
});
}, 'ReadableStreamTee should only pull enough to fill the emptiest queue');
promise_test(t => {
const rs = recordingReadableStream({}, { highWaterMark: 0 });
const theError = { name: 'boo!' };
rs.controller.error(theError);
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
return flushAsyncEvents().then(() => {
assert_array_equals(rs.events, [], 'pull should not be called');
return Promise.all([
promise_rejects_exactly(t, theError, reader1.closed),
promise_rejects_exactly(t, theError, reader2.closed)
]);
});
}, 'ReadableStreamTee should not pull when original is already errored');
for (const branch of [1, 2]) {
promise_test(t => {
const rs = recordingReadableStream({}, { highWaterMark: 0 });
const theError = { name: 'boo!' };
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
return flushAsyncEvents().then(() => {
assert_array_equals(rs.events, ['pull'], 'pull should be called once');
rs.controller.enqueue('a');
const reader = (branch === 1) ? reader1 : reader2;
return reader.read();
}).then(() => flushAsyncEvents()).then(() => {
assert_array_equals(rs.events, ['pull', 'pull'], 'pull should be called twice');
rs.controller.error(theError);
return Promise.all([
promise_rejects_exactly(t, theError, reader1.closed),
promise_rejects_exactly(t, theError, reader2.closed)
]);
}).then(() => flushAsyncEvents()).then(() => {
assert_array_equals(rs.events, ['pull', 'pull'], 'pull should be called twice');
});
}, `ReadableStreamTee stops pulling when original stream errors while branch ${branch} is reading`);
}
promise_test(t => {
const rs = recordingReadableStream({}, { highWaterMark: 0 });
const theError = { name: 'boo!' };
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
return flushAsyncEvents().then(() => {
assert_array_equals(rs.events, ['pull'], 'pull should be called once');
rs.controller.enqueue('a');
return Promise.all([reader1.read(), reader2.read()]);
}).then(() => flushAsyncEvents()).then(() => {
assert_array_equals(rs.events, ['pull', 'pull'], 'pull should be called twice');
rs.controller.error(theError);
return Promise.all([
promise_rejects_exactly(t, theError, reader1.closed),
promise_rejects_exactly(t, theError, reader2.closed)
]);
}).then(() => flushAsyncEvents()).then(() => {
assert_array_equals(rs.events, ['pull', 'pull'], 'pull should be called twice');
});
}, 'ReadableStreamTee stops pulling when original stream errors while both branches are reading');
promise_test(async () => {
const rs = recordingReadableStream();
const [reader1, reader2] = rs.tee().map(branch => branch.getReader());
const branch1Reads = [reader1.read(), reader1.read()];
const branch2Reads = [reader2.read(), reader2.read()];
await flushAsyncEvents();
rs.controller.enqueue('a');
rs.controller.close();
assert_object_equals(await branch1Reads[0], { value: 'a', done: false }, 'first chunk from branch1 should be correct');
assert_object_equals(await branch2Reads[0], { value: 'a', done: false }, 'first chunk from branch2 should be correct');
assert_object_equals(await branch1Reads[1], { value: undefined, done: true }, 'second read() from branch1 should be done');
assert_object_equals(await branch2Reads[1], { value: undefined, done: true }, 'second read() from branch2 should be done');
}, 'ReadableStream teeing: enqueue() and close() while both branches are pulling');
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