Preloading Emscripten-generated JS module in a Worker

I'm having issues preloading a JS/WASM library in a CF Worker - the JS library starts as C++ and then gets transpiled to JS with Emscripten and CMake. I'm transpiling with ES6_SYNTAX and MODULARIZED enabled.

I include this JS/WASM library

sparks.js

sparks.js

sparks.js

sparks.js into the Cloudflare Worker project which I called

hello-wrangler

hello-wrangler

hello-wrangler

hello-wrangler.

Below is my

index.ts

index.ts

in the

hello-wrangler

hello-wrangler

hello-wrangler

hello-wrangler project. I do the imports and then I call

loadModule()

loadModule()

loadModule()

loadModule() in a

useEffect

useEffect

useEffect

useEffect in hopes to have the module load proactively.
It should be available for any route or action.
I'm trying to setup an action on

localhost:8787/

localhost:8787/

localhost:8787/

localhost:8787/ to print out the module instance,

libptr

libptr

libptr

libptr.
I always end up with the null condition,

return c.text("No libptr");

return c.text("No libptr");

return c.text("No libptr");

return c.text("No libptr");

import { Hono } from 'hono';
import { useEffect, useState } from 'hono/jsx';

// The JS/C++ library Module and Lib class
import Module from './sparks';
import { Lib } from './sparks';

const [libptr, setLibptr] = useState<Lib | null>(null);

const loadModule = async (): Promise<void> => {
    const activeModule = await Module();
    if (activeModule) {
        let inst = activeModule.Lib.get_instance("Lib", 1.0);
        if (inst) {
            setLibptr(inst);
            inst.description = "Updated from JS";
            inst.version = 2.2;
            console.log(inst.to_str());
        } else {
            console.error("Failed to create Lib instance");
        }
    } else {
        console.error("Failed to load Module");
    }
}

useEffect(() => {
    // Load module on page mount
    loadModule();

    return () => {
            libptr.delete();
        }
    }
}, []);

const app = new Hono<{ Bindings: Bindings }>();

app.use('/', async c => {
    if (libptr) {
        return c.text(`libptr:\n\t${libptr.to_str()}`);
    } else {
        // Always prints out this response
        return c.text("No libptr");
    }
    
});

export default app;

import { Hono } from 'hono';
import { useEffect, useState } from 'hono/jsx';

// The JS/C++ library Module and Lib class
import Module from './sparks';
import { Lib } from './sparks';

const [libptr, setLibptr] = useState<Lib | null>(null);

const loadModule = async (): Promise<void> => {
    const activeModule = await Module();
    if (activeModule) {
        let inst = activeModule.Lib.get_instance("Lib", 1.0);
        if (inst) {
            setLibptr(inst);
            inst.description = "Updated from JS";
            inst.version = 2.2;
            console.log(inst.to_str());
        } else {
            console.error("Failed to create Lib instance");
        }
    } else {
        console.error("Failed to load Module");
    }
}

useEffect(() => {
    // Load module on page mount
    loadModule();

    return () => {
            libptr.delete();
        }
    }
}, []);

const app = new Hono<{ Bindings: Bindings }>();

app.use('/', async c => {
    if (libptr) {
        return c.text(`libptr:\n\t${libptr.to_str()}`);
    } else {
        // Always prints out this response
        return c.text("No libptr");
    }
    
});

export default app;

import { Hono } from 'hono';
import { useEffect, useState } from 'hono/jsx';

// The JS/C++ library Module and Lib class
import Module from './sparks';
import { Lib } from './sparks';

const [libptr, setLibptr] = useState<Lib | null>(null);

const loadModule = async (): Promise<void> => {
    const activeModule = await Module();
    if (activeModule) {
        let inst = activeModule.Lib.get_instance("Lib", 1.0);
        if (inst) {
            setLibptr(inst);
            inst.description = "Updated from JS";
            inst.version = 2.2;
            console.log(inst.to_str());
        } else {
            console.error("Failed to create Lib instance");
        }
    } else {
        console.error("Failed to load Module");
    }
}

useEffect(() => {
    // Load module on page mount
    loadModule();

    return () => {
            libptr.delete();
        }
    }
}, []);

const app = new Hono<{ Bindings: Bindings }>();

app.use('/', async c => {
    if (libptr) {
        return c.text(`libptr:\n\t${libptr.to_str()}`);
    } else {
        // Always prints out this response
        return c.text("No libptr");
    }
    
});

export default app;

import { Hono } from 'hono';
import { useEffect, useState } from 'hono/jsx';

// The JS/C++ library Module and Lib class
import Module from './sparks';
import { Lib } from './sparks';

const [libptr, setLibptr] = useState<Lib | null>(null);

const loadModule = async (): Promise<void> => {
    const activeModule = await Module();
    if (activeModule) {
        let inst = activeModule.Lib.get_instance("Lib", 1.0);
        if (inst) {
            setLibptr(inst);
            inst.description = "Updated from JS";
            inst.version = 2.2;
            console.log(inst.to_str());
        } else {
            console.error("Failed to create Lib instance");
        }
    } else {
        console.error("Failed to load Module");
    }
}

useEffect(() => {
    // Load module on page mount
    loadModule();

    return () => {
            libptr.delete();
        }
    }
}, []);

const app = new Hono<{ Bindings: Bindings }>();

app.use('/', async c => {
    if (libptr) {
        return c.text(`libptr:\n\t${libptr.to_str()}`);
    } else {
        // Always prints out this response
        return c.text("No libptr");
    }
    
});

export default app;

One thing I already tried to do is to add

await loadModule()

await loadModule()

await loadModule()

await loadModule() which did not succeed (instead got 500 error). Thanks.

Preloading Emscripten-generated JS module in a Worker

Similar Threads

Similar Threads

Similar Threads