Wait for future promise / fiber and return it's value

[smac89]

I think I am still not understanding how these fibers work. To demonstrate the problem I am facing, I took the fibonacci example from the readme and changed it to match what I am trying to do

import Fiber from "fibers";

function Fibonacci(): () => number {
    // Create a new fiber which yields sequential Fibonacci numbers
    const fiber: Fiber = Fiber(() => {
        const curFib = Fiber.current!;

        process.nextTick(() => {
            curFib.run();
            for (let [prev, curr] = [1, 0]; ; [prev, curr] = [curr, prev + curr]) {
                Fiber.yield(curr); // This `yield` is problematic
            }
        });

        Fiber.yield();
    });
    // Return a bound handle to `run` on this fiber
    return fiber.run.bind(fiber);
}

const seq = Fibonacci();
for (let ii = seq(); ii <= 1597; ii = seq()) {
    console.log(ii);
}

The error I get is:

Error: yield() called with no fiber running
    at Function.yield (/home/chigozirim/WebstormProjects/example/node_modules/fibers/fibers.js:90:16)
    at process.nextTick (/home/chigozirim/WebstormProjects/example/main.ts:13:28)
    at process._tickCallback (internal/process/next_tick.js:61:11)
    at Function.Module.runMain (internal/modules/cjs/loader.js:757:11)
    at Object.<anonymous> (/home/chigozirim/.nvm/versions/node/v10.15.3/lib/node_modules/ts-node/src/bin.ts:158:12)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
    at Function.Module._load (internal/modules/cjs/loader.js:531:3)

My assumption with fiber is that I can have an async method and as long as I wrap it in a Fiber, I am able to wait for it to finish by calling fiber.run which will wait for the first call to Fiber.yield before continuing.

I also tried doing this by wrapping the call in a Future, but calling future.wait, actually fails because the call needs to wrapped in a Fiber...

How do I actually make async calls, synchronous using Fibers or Futures? This is the main reason why I wanted to use this library in the first place.

[laverdet]

process.nextTick will run at the start of the next tick in a callback and will not be in a fiber.