Simple WASM Rust async executor + spawn_future helper

altv_esbuild_rust_wasm_example.js

// js usage example for https://github.com/xxshady/altv-esbuild-rust-wasm

import alt from "alt-shared"
import loadWasm from "./rust-wasm/pkg/rust_wasm_bg.wasm"

const { on_every_tick } = loadWasm({})

alt.everyTick(on_every_tick);

async_executor.rs

// Make sure to install "futures" crate
use futures::{
    executor::{LocalPool, LocalSpawner},
    task::LocalSpawnExt,
    task::SpawnError,
};
use std::{cell::RefCell, future::Future};

thread_local! {
    pub(crate) static EXECUTOR_INSTANCE: RefCell<Executor> = Default::default();
}

#[derive(Debug)]
pub(crate) struct Executor {
    pool: LocalPool,
    spawner: LocalSpawner,
}

impl Executor {
    pub(crate) fn run(&mut self) {
        self.pool.run_until_stalled();
    }
}

impl Default for Executor {
    fn default() -> Self {
        let pool = LocalPool::new();
        let spawner = pool.spawner();
        Self { pool, spawner }
    }
}

pub fn spawn_future<F>(future: F) -> Result<(), SpawnError>
where
    F: Future<Output = ()> + 'static,
{
    EXECUTOR_INSTANCE.with_borrow(|executor| executor.spawner.spawn_local(future))
}

// needs to be called from JS in every tick (a.k.a setInterval with 0 delay)
#[wasm_bindgen]
pub fn on_every_tick() {
    EXECUTOR_INSTANCE.with_borrow_mut(|executor| {
        executor.run();
    });
}

usage_example.rs

spawn_future(async {
  // ...
})
.unwrap();