Async Await Promise.all Array.map not behaving as expected. Not Sure Why

Question

I have the below in an async function in one of my projects. matchCamera, matchIP, and matchAudio all return either boolean, or an error.

If an error gets returned I would expect for it to fall into my master catch so I can handle it, but this isn't happening.

try {
    // .... Additional code here

    const typecheck = await Promise.all(
        evoCfg.cameras.map(async camera => {
            if (camera.type === 'H264') {
                return await matchCamera(camera);
            } else if (camera.type === 'RTSP') {
                return await matchIP(camera);
            } else if (camera.type === 'AUDIO') {
                return await matchAudio(camera);
            } else {
                // Motion JPEG
                return true;
            }
        })
    );

    //  .... additional code here

    console.log('results:);
    console.dir(typecheck, {depth: null, colors: true});
} catch (e) {
    console.error('In Master Catch:', e);
}

My output that I keep getting when I cause an error condition is:

results:
[ true,
true,
true,
true,
true,
true,
Error: MAC for IP Cam not found on Network: 00:11:22:33:44:55
  at matchIP (/file.js:58:15)
  at process._tickCallback (internal/process/next_tick.js:68:7),
true ]

I am expecting:

In Master Catch: MAC for IP Cam not found on Network: 00:11:22:33:44:55
  at matchIP (/file.js:58:15)
  at process._tickCallback (internal/process/next_tick.js:68:7)

---

const matchIP = async source => {
    let arpScan = [];

    for (const c in obj.arr){
        if(obj.arr[c].name === source.source) {
            try {
                arpScan = await scannerP();

                let arpIdx = searchObjArray(source.mac, source.mac, 'mac', 'mac', arpScan);
                if(arpIdx === -1) {
                    // not found on network
                    throw new Error(`MAC for IP Cam not found on Network: ${source.mac}`);
                }

                for (const cs in obj.arr[c].sources) {
                    if (
                        obj.arr[c].sources[cs].id === arpScan[arpIdx].mac &&
                        obj.arr[c].sources[cs].url === `rtsp://${arpScan[arpIdx].ip}/${source.streamPort}`
                        ) {
                        return true;
                    }
                }
                let recorderIdx = searchObjArray(
                    'rtsp',
                    source.mac,
                    'fmt',
                    'id',
                    obj.arr[c].sources
                );

                source.streamAddress = arpScan[arpIdx].ip;
                obj.arr[c].sources[recorderIdx].url = `rtsp://${arpScan[arpIdx].ip}/${source.streamPort}`;
                return false;
            } catch (e) {
                return e;
            }
        }
    }
};

Answer 1

The problem is that your matchIP function has in it

try {
  // ... code
catch (e) {
  return e;
}

So it is returning the error as a value rather than throwing it for your outer block to catch.

Also, as other people have pointed out. You are mostly defeating the value of Promise.all by using await in your map function. Take the awaits out.