Running Non-blocking Code

JSCore runs JavaScript in a blocking manner - the entire game will wait for your JavaScript code to finish running before rendering the next frame. So a web request that takes 5 seconds will freeze your game for 5 seconds.

In this case, you can run the code in a new thread without blocking the game.

myWebRequestRunnable.spawn();

// And it too can take arguments.
myWebRequestRunnable.spawn("argument 1", "argument 2");

Maintaining Execution Order

If you spawn a runnable in a new thread, there is no guarantee in the order of execution.

myRunnable.spawn(); // this prints out 'hi'
console.log("and then this");

It is possible that 'hi' gets printed before 'and then this', but it is also possible that 'and then this' comes before 'hi'.

You can maintain order by using JavaScript Callbacks, for example.

thisRunnablePrintsHiAndThen.spawn(() => {
  console.log("and then this");
});

JSCore does not support setTimeout due to runtime restriction.

Preventing Callback Hell

Callback hell is when there are multiple levels of callback functions, this is particularly a problem in JSCore as each time .spawn() is called, a new thread is spawned to run the code, which is a slow and expensive task.

Take this runnable callback hell for example.

// ... some code before

runnableAndThen.spawn(() => {
  anotherRunnableAndThen.spawn(() => {
    anotherAnotherRunnableAndThen.spawn(() => {
      console.log("Reached the end");
    });
  });
});

// some code after ...

We used runnableAndThen.spawn( ... ) because we don't want to block execution of the main press, this code is suboptimal because by the time we reach console.log, we have created 3 threads, and spawning new threads is slow.

To avoid this, .spawn() should be used only when absolutely necessary. In this case, the code can be refactored to use only a singular callback, maintain the execution of the functions, and not blocking the main thread.

// ... some code before

runnableAndThen.spawn(() => {
  anotherRunnable.runF();
  anotherAnotherRunnable.runF();
  console.log("Reached the end");
});

// some code after ...