async-interval-timer
Use Case
You want some piece of code to run repeatedly, with an n-millisecond wait in between completed runs. The piece of code that you want to run may be asynchronous. Example: every 30 seconds, asynchronously pull an update from a REST API and check for some condition; stop the timer when the condition is true.
Info
The main point of the timer is this: the callback is not guaranteed to be called every n milliseconds, but there is guaranteed to be a wait of n milliseconds between the end of the callback's execution, and the next calling of the callback. Optionally works with asyncawait.
How it Works
Instantiate a Timer instance
- specify an interval (number of milliseconds)
- specify a callback
- specify any other (non-required) options
- start the timer
- stop the timer when desired
Options
runFirst: optionally, call the callback immediately upon starting the timer. Otherwise, the callback will be called for the first time, after one interval duration (the default).
Async Callbacks
Following the asyncawait paradigm, if your callback is an awaitable (async()), you can optionally start the timer with startAsync() instead of start(); this will ensure that the wait interval doesn't start until execution of the async callback is completely done.
Usage:
Instantiation
const Timer = ; //prints 'hi' every 1000 ms const timer = 1000 { console}; // - or - const timer = 1000; timer;
Starting
//if interval && callback already specified timerstart; //if callback not yet specified (or to change it) timerstart { console}; //call with 'runFirst' optiontimerstart { console} true;
Change the Interval While Running
//if interval && callback already specified timerstart; //increase interval to every minutetimer;
Stop the Timer
const duration = timer; console;
Run Async Code
const Timer = ; //asynchronous method const asyncMethod = async { //some asynchronous operation }; //call asyncMethod every secondconst timer = 1000 asyncMethod; //start timer timer;