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FAQ: Just say there's a polyfill #1581

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32 changes: 3 additions & 29 deletions FAQ.md
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Expand Up @@ -53,35 +53,9 @@ WebAssembly was designed with [a variety of use cases in mind](UseCases.md).

## Can WebAssembly be polyfilled?

We think so. There was an early
[prototype](https://github.com/WebAssembly/polyfill-prototype-1) with demos
[[1](https://lukewagner.github.io/AngryBotsPacked),
[2](https://lukewagner.github.io/PlatformerGamePacked)], which showed
that decoding a binary WebAssembly-like format into asm.js can be efficient.
And as the WebAssembly design has changed there have been
[more](https://github.com/WebAssembly/polyfill-prototype-2)
[experiments](https://github.com/WebAssembly/binaryen/blob/master/src/wasm2asm.h)
with polyfilling.

Overall, optimism has been increasing for quick adoption of WebAssembly in
browsers, which is great, but it has decreased the motivation to work on a
polyfill.

It is also the case that polyfilling WebAssembly to asm.js is less urgent
because of the existence of alternatives, for example, a reverse polyfill -
compiling
[asm.js to WebAssembly](https://github.com/WebAssembly/binaryen/blob/master/src/asm2wasm.h) -
exists, and it allows shipping a single build that can run as either
asm.js or WebAssembly. It is also possible to build a project into
two parallel asm.js and WebAssembly builds by just
[flipping a switch](https://github.com/kripken/emscripten/wiki/WebAssembly)
in emscripten, which avoids polyfill time on the client entirely. A third
option, for non-performant code, is to use a compiled WebAssembly interpreter
such as
[binaryen.js](https://github.com/WebAssembly/binaryen/blob/master/test/binaryen.js/test.js).

However, a WebAssembly polyfill is still an interesting idea and should in
principle be possible.
Yes. Transpiling to ECMAScript is implemented in [wasm2js][], a part of binaryen.

[wasm2js]: https://github.com/WebAssembly/binaryen/blob/main/src/wasm2js.h


## Is WebAssembly only for C/C++ programmers?
Expand Down