Console warning: using deprecated parameters for the initialization function; pass a single object instead

[yescallop]

When running a Leptos CSR app with Trunk in the browser, I always get this warning in the console:

using deprecated parameters for the initialization function; pass a single object instead

It is triggered by the __wbg_init function in the JS file:

async function __wbg_init(module_or_path) {
    if (wasm !== undefined) return wasm;


    if (typeof module_or_path !== 'undefined') {
        if (Object.getPrototypeOf(module_or_path) === Object.prototype) {
            ({module_or_path} = module_or_path)
        } else {
            console.warn('using deprecated parameters for the initialization function; pass a single object instead')
        }
    }
    ...
}

Because the argument to this function in index.html is a string instead of an object:

import init, * as bindings from '/c6ol-client-27e2b4451d2c072.js';
const wasm = await init('/c6ol-client-27e2b4451d2c072_bg.wasm');

I tracked this down to this commit in wasm-bindgen, which is shipped in v0.2.93 and onwards. The corresponding pull request is rustwasm/wasm-bindgen#3995.

The corresponding code in Trunk are these lines:

trunk/src/pipelines/rust/output.rs

Lines 140 to 141 in ce872ce

	import init{import} from '{base}{js}';
	const wasm = await init('{base}{wasm}');

I think we can maybe change the second line to pass an object instead of a string, but we need to be careful not to break compatibility with wasm-bindgen before v0.2.93. I might investigate this later and open a PR for this.

[ctron]

Would previous versions also accept an object?

[ctron]

Just checked, look like it doesn't. So we indeed need to eval the version.

[robofinch]

I don't think this completely fixes the issue. I've been getting this console warning when starting web workers with gloo-worker, and traced it back to a temporary file containing

importScripts("http://localhost:8080/web_worker.js"); wasm_bindgen("http://localhost:8080/web_worker_bg.wasm");

(The exact URLs don't matter.) I'm fairly certain the file was generated by

trunk/src/pipelines/rust/mod.rs

Lines 656 to 658 in 4c9d85f

	WasmBindgenTarget::NoModules => format!(
	r#"importScripts("./{hashed_js_name}");wasm_bindgen("./{hashed_wasm_name}");"#,
	),

wasm_bindgen refers to / runs __wbg_init, so the same issue as above occurs.

Edit: I half take it back, I found where the file was generated in gloo-worker, I'll submit an issue there. Though the above code still should probably use the new format for __wbg_init. Incidentally, the same issue probably appears in

trunk/examples/webworker/src/bin/app.rs

Lines 12 to 16 in 4c9d85f

	let script = Array::new();
	script.push(
	&format!(r#"importScripts("{origin}/{name}.js");wasm_bindgen("{origin}/{name}_bg.wasm");"#)
	.into(),
	);