Async job in custom order

custom-async-order.js

/*
H ~~~~ ->
A -> B ->
          C -> D

H: high priority long task, should start in parallel to A
A: first task
B: should start once A is finished
C: should start once B & H is finished
D: should start once C is finished
*/

function task(x,sec) {
  return new Promise(resolve => {
  console.log('Start: ' + x);
    setTimeout(() => {
        console.log('End: ' + x);
      resolve(x);
    }, sec *1000);
  });
}

async function run() {
  h = task('H', 5);
  a = task('A',1);
  b = await a && task('B', 1);
  c = await h && b && task('C', 1);
  await c && task('D', 1);
}
run();


/* OUTPUT

Start: H
Start: A
{ [[PromiseStatus]]:pending, [[PromiseValue]]:undefined }
End: A
Start: B
End: B
End: H
Start: C
End: C
Start: D
End: D

*/