Function singleItem

Queue of a single item, only once, allows for simple synchronisation.

It has a 'first write wins' behaviour

const q = new WaitForValue(); // or singleItem();

// In some part of the code add a value
const value = q.add(`some-val`);

// Somewhere else, wait for value
await q.get(value);
Copy

It is not possible to add a second item (an exception will throw), however it is possible to call get as many times as you need.

The .isUsed property allows you to to check if a value has been already added to the queue.

Based on: https://2ality.com/2024/05/proposal-promise-with-resolvers.html