convert recursive calling inside Promise.then() into a loop?

Question

I need to recursively call a function itself inside a .then() method. Something like this:

function poll(params) { 
    const returned_promise = read_from_backend(some_url, some_params);
    returned_promise
       .then(some_process_func)
       .then(r => {
            poll(some_params); // recursive call
        })   
}

poll(starting_params);

Is there a way to write this algorithm in a while loop, without blocking the main thread?

Answer 1

Here's a way to write the algorithm with a while loop. Since we're working with async code via Promises, we won't be blocking the main thread.

async function poll(params) {
    while (true) {
        await new Promise(resolve => setTimeout(resolve, 1000)) // perhaps sleep a bit between polls
        const returned_promise = read_from_backend(some_url, some_params);
        const r = await returned_promise.then(some_process_func)
    }
}

poll(starting_params);