RunasSudo/Cargo.toml

## Cargo.toml
[package]
name = "asyncify-vanilla"
version = "0.1.0"
authors = ["RunasSudo <runassudo@yingtongli.me>"]
edition = "2018"

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

[dependencies]
wasm-bindgen = "0.2.74"

## index.html
<!DOCTYPE html>
<html>
	<head><meta charset="utf-8"></head>
	<body>
		<script src="asyncify_vanilla.js"></script>
		<script>
			var wasmRaw;
			const DATA_ADDR = 16;
			const DATA_START = DATA_ADDR + 8;
			const DATA_END = 1024;

			function get_second_number() {
				if (wasmRaw.asyncify_get_state() === 0) { // Normal execution
					setTimeout(secondNumberCallback, 1000); // Simulate async function queued

					// Unwind the stack
					wasmRaw.asyncify_start_unwind(DATA_ADDR);
					return null;
				} else {
					// Finished rewinding
					wasmRaw.asyncify_stop_rewind();
					return 5;
				}
			}

			function secondNumberCallback() {
				// Rewind the stack and resume execution
				wasmRaw.asyncify_start_rewind(DATA_ADDR);

				alert(wasmRaw.add_two_numbers()); // Should alert "5"
			}

			async function init() {
				wasmRaw = await wasm_bindgen("asyncify_vanilla_async.wasm");

				new Int32Array(wasmRaw.memory.buffer, DATA_ADDR).set([DATA_START, DATA_END]);

				let result = wasm_bindgen.add_two_numbers(10);

				if (wasmRaw.asyncify_get_state() !== 0) { // 0 if normal, 1 if unwinding, 2 if rewinding
					// Stack unwinding so ignore the result
				} else {
					alert(result); // Unreachable
				}
			}

			init();
		</script>
	</body>
</html>

## lib.rs
use wasm_bindgen::prelude::*;

#[wasm_bindgen]
extern "C" {
	fn get_second_number() -> u32;
}

#[wasm_bindgen]
pub fn add_two_numbers(first_number: u32) -> u32 {
	let second_number = get_second_number();
	return first_number + second_number;
}
	[package]
	name = "asyncify-vanilla"
	version = "0.1.0"
	authors = ["RunasSudo <runassudo@yingtongli.me>"]
	edition = "2018"

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

	[dependencies]
	wasm-bindgen = "0.2.74"
	<!DOCTYPE html>
	<html>
	<head><meta charset="utf-8"></head>
	<body>
	<script src="asyncify_vanilla.js"></script>
	<script>
	var wasmRaw;
	const DATA_ADDR = 16;
	const DATA_START = DATA_ADDR + 8;
	const DATA_END = 1024;

	function get_second_number() {
	if (wasmRaw.asyncify_get_state() === 0) { // Normal execution
	setTimeout(secondNumberCallback, 1000); // Simulate async function queued

	// Unwind the stack
	wasmRaw.asyncify_start_unwind(DATA_ADDR);
	return null;
	} else {
	// Finished rewinding
	wasmRaw.asyncify_stop_rewind();
	return 5;
	}
	}

	function secondNumberCallback() {
	// Rewind the stack and resume execution
	wasmRaw.asyncify_start_rewind(DATA_ADDR);

	alert(wasmRaw.add_two_numbers()); // Should alert "5"
	}

	async function init() {
	wasmRaw = await wasm_bindgen("asyncify_vanilla_async.wasm");

	new Int32Array(wasmRaw.memory.buffer, DATA_ADDR).set([DATA_START, DATA_END]);

	let result = wasm_bindgen.add_two_numbers(10);

	if (wasmRaw.asyncify_get_state() !== 0) { // 0 if normal, 1 if unwinding, 2 if rewinding
	// Stack unwinding so ignore the result
	} else {
	alert(result); // Unreachable
	}
	}

	init();
	</script>
	</body>
	</html>
	use wasm_bindgen::prelude::*;

	#[wasm_bindgen]
	extern "C" {
	fn get_second_number() -> u32;
	}

	#[wasm_bindgen]
	pub fn add_two_numbers(first_number: u32) -> u32 {
	let second_number = get_second_number();
	return first_number + second_number;
	}