wut?

async.js

#!/usr/bin/env node 
const inputs = [false, false, false, true, false, false];

const fast = (i, d) => {
	console.log(`run ${d}`);
	return i;
};

const slow = async (i) => {
	return new Promise((resolve, reject) => {
		setTimeout(() => {
			if (i) {
				throw new Error(`inside error`);
			}
			return resolve(i);
		}, 3000);
	});
};

inputs.forEach(async (i, d) => {
	try {
		const a = await slow(fast(i, d));

		if (a) {
			throw new Error('errored');
		}

		console.log(`${d} done`);
	} catch (err) {
		console.log(err);
	}
});

async_expected.md

Expected:

run 0
run 1
run 2
run 3
run 4
run 5
done 0
done 1
done 2
<ERROR>

Actual:

run 0
run 1
run 2
run 3
run 4
run 5
rando.js:13
				throw new Error(`inside error`);
				^

Error: inside error
    at Timeout.setTimeout [as _onTimeout] (rando.js:13:11)
    at ontimeout (timers.js:424:11)
    at tryOnTimeout (timers.js:288:5)
    at listOnTimeout (timers.js:251:5)
    at Timer.processTimers (timers.js:211:10)

variant.js

#!/usr/bin/env node
const inputs = [false, false, false, true, false, false];

const fast = (i, d) => {
	console.log(`run ${d}`);
	// pass d to slow
	return [i, d];
};

const slow = async ([i, d]) => {
	return new Promise((resolve, reject) => {
		setTimeout(() => {
			if (i) {
				throw new Error(`inside error`);
			}
			return resolve(i);
      
	    	// multiply wait time by d
		}, 100 * d);
	});
};

inputs.forEach(async (i, d) => {
	try {
		const a = await slow(fast(i, d));

		if (a) {
			throw new Error('errored');
		}

		console.log(`${d} done`);
	} catch (err) {
		console.log(err);
	}
});

variant_out.md

run 0
run 1
run 2
run 3
run 4
run 5
0 done
1 done
2 done
rando.js:13
				throw new Error(`inside error`);
				^

Error: inside error
    at Timeout.setTimeout [as _onTimeout] (rando.js:13:11)
    at ontimeout (timers.js:424:11)
    at tryOnTimeout (timers.js:288:5)
    at listOnTimeout (timers.js:251:5)
    at Timer.processTimers (timers.js:211:10)