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// |reftest| skip-if(!xulRuntime.shell) -- needs drainJobQueue
if ("ignoreUnhandledRejections" in this) {
ignoreUnhandledRejections();
}
// Spot-check subclassing of stream constructors.
// ReadableStream can be subclassed.
class PartyStreamer extends ReadableStream {}
// The base class constructor is called.
let started = false;
let stream = new PartyStreamer({
// (The ReadableStream constructor calls this start method.)
start(c) { started = true; }
});
drainJobQueue();
assertEq(started, true);
// The instance's prototype chain is correct.
assertEq(stream.__proto__, PartyStreamer.prototype);
assertEq(stream.__proto__.__proto__, ReadableStream.prototype);
assertEq(stream.__proto__.__proto__.__proto__, Object.prototype);
assertEq(stream.__proto__.__proto__.__proto__.__proto__, null);
assertEq(stream instanceof ReadableStream, true);
// Non-generic methods can be called on the resulting stream.
let reader = stream.getReader();
assertEq(stream.locked, true);
// CountQueuingStrategy can be subclassed.
class PixelStrategy extends CountQueuingStrategy {}
assertEq(new PixelStrategy({highWaterMark: 4}).__proto__, PixelStrategy.prototype);
// The base class constructor is called.
assertThrowsInstanceOf(() => new PixelStrategy, TypeError);
assertEq(new PixelStrategy({highWaterMark: -1}).highWaterMark, -1);
// VerySmartStrategy can be subclassed.
class VerySmartStrategy extends ByteLengthQueuingStrategy {
size(chunk) {
return super.size(chunk) * 8;
}
}
let vss = new VerySmartStrategy({highWaterMark: 12});
assertEq(vss.size(new ArrayBuffer(8)), 64);
assertEq(vss.__proto__, VerySmartStrategy.prototype);
// Even ReadableStreamDefaultReader can be subclassed.
async function readerTest() {
const ReadableStreamDefaultReader = new ReadableStream().getReader().constructor;
class MindReader extends ReadableStreamDefaultReader {
async read() {
let foretold = {value: "death", done: false};
let actual = await super.read();
actual = foretold; // ZOMG I WAS RIGHT, EXACTLY AS FORETOLD they should call me a righter
return actual;
}
}
let stream = new ReadableStream({
start(c) { c.enqueue("one"); c.enqueue("two"); },
pull(c) { c.close(); }
});
let reader = new MindReader(stream);
let result = await reader.read();
assertEq(result.value, "death");
reader.releaseLock();
reader = stream.getReader();
result = await reader.read();
assertEq(result.done, false);
assertEq(result.value, "two");
result = await reader.read();
assertEq(result.done, true);
assertEq(result.value, undefined);
}
runAsyncTest(readerTest);
// Even ReadableStreamDefaultController, which can't be constructed,
// can be subclassed.
let ReadableStreamDefaultController;
new ReadableStream({
start(c) {
ReadableStreamDefaultController = c.constructor;
}
});
class MasterController extends ReadableStreamDefaultController {
constructor() {
// don't call super, it'll just throw
return Object.create(MasterController.prototype);
}
}
let c = new MasterController();
// The prototype chain is per spec.
assertEq(c instanceof ReadableStreamDefaultController, true);
// But the instance does not have the internal slots of a
// ReadableStreamDefaultController, so the non-generic methods can't be used.
assertThrowsInstanceOf(() => c.enqueue("horse"), TypeError);
if (typeof reportCompare === 'function') {
reportCompare(0, 0);
}
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