Is there a way to inspect the pending queue size?

Yes, you can inspect the pending queue size using the pendingCount property on the limit function.

According to [index.d.ts:L9-L12], pendingCount is a read-only property that returns "The number of promises that are waiting to run (i.e. their internal fn was not called yet)."

Here's how you'd use it:

import pLimit from 'p-limit';

const limit = pLimit(1);

limit(() => fetchSomething('foo'));
limit(() => fetchSomething('bar'));
limit(() => fetchSomething('baz'));

console.log(limit.pendingCount); // Shows how many tasks are queued

This is demonstrated in the test file [test.js:L186-L188], where it checks that pendingCount correctly reflects the number of pending tasks before and after calling clearQueue().

There's also a companion property activeCount [index.d.ts:L5-L7] if you need to know how many promises are currently running.

FOLLOW_UPS:

• How do activeCount and pendingCount differ?
• Can I dynamically adjust the concurrency limit?
• What happens when clearQueue() is called?