I'm trying to create a timed scheduler that can execute tasks in parallel. For example:
Let's say I'm trying to create a function that will do something after 10 seconds of being called. After calling Process_1(), it will be expected to run its intended functionality after 10 seconds.
But at the 5 second mark while Process_1() is waiting to be executed at the halfway point, I'm now calling Process_2() midway. So at the 10 seconds mark, Process_1() will execute its function and at the 15 seconds mark, Process_2() will execute its function.
I've tried using node-cron for this but it doesn't seem like it can schedule things in parallel. Thanks in advance!
Nodejs runs your Javascript in a single thread unless you explicitly create a WorkerThread and run some code in that. True parallel execution where both jobs are running code that uses the CPU will only be accomplished if you either run each task in a WorkerThread or child process to get it out of the main thread.
Let me repeat, true parallel execution requires more than one thread or process in nodejs and nodejs does not do that by default so you will have to create a WorkerThread or child_process.
So, if you have code that takes more than a few ms to do its work and you want it to run at a fairly precise time, then you can't count on the main Javascript thread to do that because it might be busy at that precise time. Timers in Javascript will run your code no earlier than the scheduled time, and when that scheduled time comes around, the event loop is ready to run them, but they won't actually run until whatever was running before finishes and returns control back to the event loop so the event loop can run the code attached to your timer.
So, if all you're mostly doing is I/O kind of work (reading/writing files or network), then your actual Javascript execution time is probably only milliseconds and nodejs can be very, very responsive to run your timers pretty close to "on time". But, if you have computationally expensive things that keep the CPU busy for much longer, then you can't count on your timers to run "on time" if you run that CPU-heavy stuff in the main thread.
What you can do, is start up a WorkerThread, set the timer in the WorkerThread and run your code in the worker thread. As long as you don't ask that WorkerThread to run anything else, it should be ready to run that timer pretty much "on time".
Now WorkerThreads do share some resources with the main thread so they aren't 100% independent (though they are close to independent). If you want 100% independence, then you can start a nodejs child process that runs a node script, sets its own timers and runs its own work in that other process.
All that said, the single threaded model works very, very well at reasonably high scale for code that is predominantly I/O code because nodejs uses non-blocking I/O so while it's waiting to read or write from file or network, the main thread is free and available to run other things. So, it will often give the appearance of running things in parallel because progress is being made on multiple fronts. The I/O itself inside the nodejs library is either natively non-blocking (network I/O) or is happening in an OS-native thread (file I/O) and the programming interface to Javascript is callback or promise based so it is also non-blocking.
I mention all this because you don't say what your two operations that you want to run in parallel are (including your actual code allows us to write more complete answers). If they are I/O or even some crypto, then they may already be non-blocking and you may achieve desired parallelism without having to use additional threads or processes.