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JS::Object#await is unavailable inside Proc converted into JS closure #459
Description
Reproducer
<html>
<script src="https://cdn.jsdelivr.net/npm/@ruby/3.3-wasm-wasi@2.6.0/dist/browser.script.iife.js"></script>
<script type="text/ruby" data-eval="async">
require "js"
JS.global.setTimeout(-> {
JS.global[:Promise].resolve.await
}, 0)
</script>
</html>browser.script.iife.js:2731 Uncaught Error: /bundle/gems/js-2.6.0/lib/js.rb:86:in `await': JS::Object#await can be called only from RubyVM#evalAsync or RbValue#callAsync JS API
If you are using browser.script.iife.js, please ensure that you specify `data-eval="async"` in your script tag
e.g. <script type="text/ruby" data-eval="async">puts :hello</script>
Or <script type="text/ruby" data-eval="async" src="path/to/script.rb"></script> (RuntimeError)
/bundle/gems/js-2.6.0/lib/js.rb:240:in `await'
eval_async:9:in `block in <main>'
at checkStatusTag (browser.script.iife.js:2731:21)
at browser.script.iife.js:2766:11
at wrapRbOperation (browser.script.iife.js:2738:18)
at callRbMethod (browser.script.iife.js:2764:14)
at RbValue.call (browser.script.iife.js:2547:30)
at browser.script.iife.js:2322:38
Workaround
Wrap the block with Fiber.new do ... end.transfer.
JS.global.setTimeout(-> {
Fiber.new do
JS.global[:Promise].resolve.await
end.transfer
}, 0)Solutions
We have several options to solve the issue
- Always enter the body of Proc in Ruby with
callAsyncinstead ofcall- https://github.com/ruby/ruby.wasm/blob/dc9921a39c42cde001478622058531fc7ebf94e4/packages/npm-packages/ruby-wasm-wasi/src/vm.ts#L101C1-L106C9
- It's no use to manually choose whether
call/callAsyncandeval/evalAsync
- Add conversion method to create an async version of JS function from proc.
- e.g.
JS.global.setTimeout(JS.async do
JS.global[:Promise].resolve.await
end, 0)
Activity