jsjolund/Cargo.toml

## Cargo.toml
[package]
edition = "2021"
name = "hello-wasm"
version = "0.1.0"

[lib]
crate-type = ["cdylib", "rlib"]

[dependencies]
js-sys = "0.3"
wasm-bindgen = "0.2"

## index.html
<!DOCTYPE html>
<html lang="en-US">
  <head>
    <meta charset="utf-8" />
    <title>hello-wasm example</title>
  </head>
  <body>
    <script type="module">
      import init, { main } from "./pkg/hello_wasm.js";
      init().then(() => {
        main();
      });
    </script>
  </body>
</html>

## lib.rs
use wasm_bindgen::{prelude::*, JsCast};

#[wasm_bindgen]
extern "C" {
    #[wasm_bindgen(js_namespace = console)]
    fn log(s: &str);
}

macro_rules! console_log {
    ($($t:tt)*) => (log(&format_args!($($t)*).to_string()))
}

#[wasm_bindgen]
pub fn main() {
    // Create an empty object
    let obj = js_sys::Object::new();
    console_log!("Object {:?}", obj);
    // Firefox:
    // Object { obj: JsValue(Object({})) }

    // Set key and value as strings work:
    let key = JsValue::from_str("key0");
    let val = JsValue::from_str("val0");
    let success = js_sys::Reflect::set(&obj, &key, &val).unwrap();
    console_log!("Object {:?}, success {}", obj, success);
    // Firefox:
    // Object { obj: JsValue(Object({"key0":"val0"})) }, success true

    // Set key as string and value as function does not:
    let key = JsValue::from_str("key1");
    let func: Closure<dyn Fn()> = Closure::wrap(Box::new(|| console_log!("hello from closure")));
    let val = func.as_ref().dyn_ref().unwrap();
    let success = js_sys::Reflect::set(&obj, &key, val).unwrap();
    console_log!("Object {:?}, success {}", obj, success);
    // Firefox:
    // Object { obj: JsValue(Object({"key0":"val0"})) }, success true

    // key1 is missing... although it is accessible
    let res = js_sys::Reflect::get(&obj, &key).unwrap();
    console_log!("Result {:?}", res);
    // Firefox:
    // Result JsValue(Function(real))
}
	[package]
	edition = "2021"
	name = "hello-wasm"
	version = "0.1.0"

	[lib]
	crate-type = ["cdylib", "rlib"]

	[dependencies]
	js-sys = "0.3"
	wasm-bindgen = "0.2"
	<!DOCTYPE html>
	<html lang="en-US">
	<head>
	<meta charset="utf-8" />
	<title>hello-wasm example</title>
	</head>
	<body>
	<script type="module">
	import init, { main } from "./pkg/hello_wasm.js";
	init().then(() => {
	main();
	});
	</script>
	</body>
	</html>
	use wasm_bindgen::{prelude::*, JsCast};

	#[wasm_bindgen]
	extern "C" {
	#[wasm_bindgen(js_namespace = console)]
	fn log(s: &str);
	}

	macro_rules! console_log {
	($($t:tt)) => (log(&format_args!($($t)).to_string()))
	}

	#[wasm_bindgen]
	pub fn main() {
	// Create an empty object
	let obj = js_sys::Object::new();
	console_log!("Object {:?}", obj);
	// Firefox:
	// Object { obj: JsValue(Object({})) }

	// Set key and value as strings work:
	let key = JsValue::from_str("key0");
	let val = JsValue::from_str("val0");
	let success = js_sys::Reflect::set(&obj, &key, &val).unwrap();
	console_log!("Object {:?}, success {}", obj, success);
	// Firefox:
	// Object { obj: JsValue(Object({"key0":"val0"})) }, success true

	// Set key as string and value as function does not:
	let key = JsValue::from_str("key1");
	let func: Closure<dyn Fn()> = Closure::wrap(Box::new(\|\| console_log!("hello from closure")));
	let val = func.as_ref().dyn_ref().unwrap();
	let success = js_sys::Reflect::set(&obj, &key, val).unwrap();
	console_log!("Object {:?}, success {}", obj, success);
	// Firefox:
	// Object { obj: JsValue(Object({"key0":"val0"})) }, success true

	// key1 is missing... although it is accessible
	let res = js_sys::Reflect::get(&obj, &key).unwrap();
	console_log!("Result {:?}", res);
	// Firefox:
	// Result JsValue(Function(real))
	}