Function nextSteps

examples/io/streams/modules/streams.js:358–390

()

		const internal = ReadableStreamAsyncIteratorBrand.get(this);
		const reader = internal.reader;
		const nextSteps = () => {
			if (internal.isFinished)
				return Promise.resolve({ value:undefined, done:true });
			assert(reader.stream !== undefined);
			const promiseRecord = createPromise();
			const readRequest = {
				chunkSteps: chunk => resolvePromise(promiseRecord, chunk),
				closeSteps: () => {
					ReadableStreamDefaultReaderRelease(reader);
					resolvePromise(promiseRecord, ReadableStreamAsyncIteratorBrand.token);
			  	},
				errorSteps: e => {
					ReadableStreamDefaultReaderRelease(reader);
					rejectPromise(promiseRecord, e);
				}
			};
			ReadableStreamDefaultReaderRead(reader, readRequest);
			return promiseRecord.promise.then(
				value => {
					internal.ongoingPromise = null;
					if (value === ReadableStreamAsyncIteratorBrand.token) {
						internal.isFinished = true;
						return { value: undefined, done: true };
					}
					return { value, done: false };
				},
				reason => {
					internal.ongoingPromise = null;
					internal.isFinished = true;
					throw reason;
				}
			);
		};
		internal.ongoingPromise = internal.ongoingPromise
			? internal.ongoingPromise.then(nextSteps, nextSteps)
			: nextSteps();