Calmm-way of doing async requests with interval?

Question

What's the most elegant way (in Calmm stack, Kefir, Karet Utils etc.) of doing repeated (infinite) async jobs with interval?

I want to get some json every 2000ms.

Example 1 (2000ms interval):

1. Fetch json (get takes 100ms)
2. Handle json
3. Wait the remaining time left on the interval, and start again from step 1

Example 2 (2000ms interval)

1. Fetch json (get takes 5000ms)
2. Handle json
3. Wait until steps 1 and 2 are finished before starting again at step 1

So in short, I want to to repeated gets (or any async work) and wait a minimum of 2000ms between requests.

I don't want the next request to fire until the previous one has finished in some way (success, fail, timeout).

Answer 1

这就是我如何使用Kefir而不诉诸Kefir.stream。请注意，下面的job将是您在每个刻度上执行的任务。我创建了一个虚拟任务，让代码工作。

let result = Kefir.repeat(() => {
    let job = Kefir.later(Math.random() * 5000);
    let wait = Kefir.later(2000).ignoreValues();
    return Kefir.merge([job, wait]);
});

下面是使用Kefir文档中的样式显示事件：

spawned 1 - job:   ------1X
spawned 1 - wait:  -----------X
spawned 1 - merge: ------1----X
spawned 2 - job:               ------------------2X
spawned 2 - wait:              -----------X
spawned 2 - merge:             ------------------2X
spawned 3 - job:                                   ---3X
spawned 3 - wait:                                  -----------X
spawned 3 - merge:                                 ---3-------X
result:            ------1-----------------------2----3--------...