thomas-jeepe/index.html

## index.html
<html>

<head>
    <script>
        var Module = {
            wasmBinaryFile: "site.wasm",
            onRuntimeInitialized: main,
        };
        function run_with_ptr(vec_ptr, cb) {
            const ptr = Module.HEAPU32[vec_ptr / 4];
            const len = Module.HEAPU32[vec_ptr / 4 + 1];
            cb(Module.HEAPU8.subarray(ptr, ptr + len));
            Module._drop_bytes(ptr);
        }
        function main() {
            run_with_ptr(Module._bytes(), arr => {
                console.assert(arr[0] == 1);
                console.assert(arr[1] == 2);
                console.assert(arr[2] == 3);
                console.assert(arr.length == 3);
                console.log("Woo: ", arr);
            })
        }
    </script>
    <script src="site.js"></script>
</head>

<body></body>

</html>

## main.rs
use std::mem;

#[repr(C)]
#[derive(Debug)]
pub struct JsBytes {
    ptr: u32,
    len: u32,
    cap: u32,
}

impl JsBytes {
    pub fn new(mut bytes: Vec<u8>) -> *mut JsBytes {
        let ptr = bytes.as_mut_ptr() as u32;
        let len = bytes.len() as u32;
        let cap = bytes.capacity() as u32;
        mem::forget(bytes);
        let boxed = Box::new(JsBytes { ptr, len, cap });
        Box::into_raw(boxed)
    }
}

#[no_mangle]
pub fn drop_bytes(ptr: *mut JsBytes) {
    unsafe {
        let boxed: Box<JsBytes> = Box::from_raw(ptr);
        Vec::from_raw_parts(boxed.ptr as *mut u8, boxed.len as usize, boxed.cap as usize);
    }
}

fn returns_vec() -> Vec<u8> {
    vec![1, 2, 3]
}

#[no_mangle]
pub fn bytes() -> *mut JsBytes {
    JsBytes::new(returns_vec())
}

pub fn main() {}
	<html>

	<head>
	<script>
	var Module = {
	wasmBinaryFile: "site.wasm",
	onRuntimeInitialized: main,
	};
	function run_with_ptr(vec_ptr, cb) {
	const ptr = Module.HEAPU32[vec_ptr / 4];
	const len = Module.HEAPU32[vec_ptr / 4 + 1];
	cb(Module.HEAPU8.subarray(ptr, ptr + len));
	Module._drop_bytes(ptr);
	}
	function main() {
	run_with_ptr(Module._bytes(), arr => {
	console.assert(arr[0] == 1);
	console.assert(arr[1] == 2);
	console.assert(arr[2] == 3);
	console.assert(arr.length == 3);
	console.log("Woo: ", arr);
	})
	}
	</script>
	<script src="site.js"></script>
	</head>

	<body></body>

	</html>
	use std::mem;

	#[repr(C)]
	#[derive(Debug)]
	pub struct JsBytes {
	ptr: u32,
	len: u32,
	cap: u32,
	}

	impl JsBytes {
	pub fn new(mut bytes: Vec<u8>) -> *mut JsBytes {
	let ptr = bytes.as_mut_ptr() as u32;
	let len = bytes.len() as u32;
	let cap = bytes.capacity() as u32;
	mem::forget(bytes);
	let boxed = Box::new(JsBytes { ptr, len, cap });
	Box::into_raw(boxed)
	}
	}

	#[no_mangle]
	pub fn drop_bytes(ptr: *mut JsBytes) {
	unsafe {
	let boxed: Box<JsBytes> = Box::from_raw(ptr);
	Vec::from_raw_parts(boxed.ptr as *mut u8, boxed.len as usize, boxed.cap as usize);
	}
	}

	fn returns_vec() -> Vec<u8> {
	vec![1, 2, 3]
	}

	#[no_mangle]
	pub fn bytes() -> *mut JsBytes {
	JsBytes::new(returns_vec())
	}

	pub fn main() {}