thingy.ts

function makePromisibleStream(streamable) {

	return {
		async then(resolve) {
			const stream = streamable();

			const returns = [];
			for await (const i of stream) {
				returns.push(i);
			}

			resolve(returns);
		},
		[Symbol.asyncIterator]() {
			return streamable();
		},
		subscribe(cb) {
			const stream = streamable();

			async function loop(value) {
				const v = await value;
				if (v.done) return;

				cb(v.value);

				loop(stream.next());
			}

			loop(stream.next());

			return () => {
				stream.return();
			};
		},
	};
}

async function* get_data() {
	yield await Promise.resolve("a");
	yield await Promise.resolve("b");
	yield await Promise.resolve("c");
}

const test = makePromisibleStream(get_data);

console.log("promise", await test);

for await (const i of test) {
	console.log("loop", i);
}

test.subscribe(value => {
	console.log("sub", value);
});