Error when executing stdweb::web:window function

[wikiwong]

Describe the Bug

After scaffolding a project using https://github.com/rustwasm/wasm-pack-template , I am encountering the follow error when attempting to invoke the stdweb::web::window function (stdweb version 0.4.18), using the npm start command of wasm-pack-template, which uses the webpack WasmPackPlugin:

lib.rs:

use wasm_bindgen::prelude::*;
use web_sys::console;
use stdweb::{web::window};

#[cfg(feature = "wee_alloc")]
#[global_allocator]
static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;

#[wasm_bindgen(start)]
pub fn main_js() -> Result<(), JsValue> {
    #[cfg(debug_assertions)]
    console_error_panic_hook::set_once();

    let w = window();
    Ok(())
}

Steps to Reproduce

1. npm init rust-webpack bug && cd bug (ensure you have at least NPM 6)
2. Include stdweb = "0.4.18" as a dependency in your Cargo.toml
3. Edit ./src/lib.rs to be what's in the description.
4. npm start
5. A webpage should open up with the error in the console.

If applicable, add a link to a test case (as a zip file or link to a repository we can clone).

Expected Behavior

let win = window();

executes without error

Actual Behavior

Attached error is thrown. Exact line below

const __wbg_cargowebsnippet1c30acb32a1994a07c75e804ae9855b43f191d63_74dac66dda56bf23 = function(arg0) {
    try {
        const ret = Object(_snippets_stdweb_fdcd3965c5b71088_inline370_js__WEBPACK_IMPORTED_MODULE_5__["__cargo_web_snippet_1c30acb32a1994a07c75e804ae9855b43f191d63"])(takeObject(arg0));
        _assertNum(ret);  // <-----!!! ERROR HERE!!!!!!
        return ret;
    } catch (e) {
        logError(e)
    }
};

Additional Context

Thank you to everyone who contributed to this project as well as stdweb. It is a beautiful thing to see collaboration such as koute/stdweb#318 taking place in the open source community. It's truly amazing what can be done when brilliant people from all over the world put their minds together.

[alexcrichton]

Thanks for the report! I think though this may be a bug in stdweb? It may be that a function is typed to return a number but it doesn't locally. I was able to reproduce this, but the return value was undefined instead of a number. Mind reopening on stdweb since I think it may not be a bug in wasm-bindgen itself?

[Pauan]

As a more meta note, stdweb currently doesn't interop very well with wasm-bindgen, so I recommend using one or the other.

For wasm-bindgen, you can use web-sys to access all of the DOM APIs.

[wikiwong]

Sure, thanks for looking!

[wikiwong]

and just to add some color, web-sys is fantastic and I'm grateful for its existence, unfortunately typed_html doesn't allow you to define click handlers as flexibly using the html! macros unless it's stdweb Output: https://github.com/bodil/typed-html/blob/master/examples/stdweb/src/main.rs#L20-L22

I really like aspects of both libraries, I feel as if web-sys is lower level, and stdweb provides some nice abstractions. It'd be great to combine the power of the two, although I understand that allowing such easy syntax to define click handlers might actually be a feature request of typed_html

[Pauan]

It'd be great to combine the power of the two, although I understand that allowing such easy syntax to define click handlers might actually be a feature request of typed_html

Indeed web-sys is intentionally low level, but that's why we created gloo, which contains high-level abstractions.

And I created a proposal to have high-level event listeners, very similar to what stdweb does.