Tasks executed in incorrect order

[nikneym]

The following code executes promises first, then microtasks (queued with queueMicrotask) and then macrotasks (timeouts) on Chrome, Firefox and Safari.

setTimeout(() => console.lp("timeout #1 completed"), 0);

queueMicrotask(() => console.lp("microtask #1 completed"));

new Promise((resolve) => {
  console.lp("promise #1 resolved");
  resolve();
});

setTimeout(() => console.lp("timeout #2 completed"), 0);

new Promise((resolve) => {
  console.lp("promise #2 resolved");
  resolve();
});

queueMicrotask(() => console.lp("microtask #2 completed"));

queueMicrotask(() => console.lp("microtask #3 completed"));

setTimeout(() => console.lp("timeout #3 completed"), 0);

Though promises are also microtasks, they're being given higher priority.
Since we're using the same queue for the timeouts and microtasks, timeouts may executed in-between microtasks:

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: promise #1 resolved

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: promise #2 resolved

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: timeout #1 completed

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: microtask #1 completed

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: microtask #2 completed

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: timeout #3 completed

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: microtask #3 completed

WARN  console : lightpanda . . . . . . . . . . . . . . . . .  [+0ms]
      args =
        1: timeout #2 completed