feat: wasm support

[mattsse]

Motivation

Add wasm support

• Close WASM Support #96

Solution

• make everything compile with --target wasm32-unknown-unknown. the biggest challenge is probably disabling transports.
• implement a wasm compatible WS provider using web_sys::WebSocket
• make sure all abi generated stuff is wasm compatible.

Afterwards we can look at how to shrink it etc.

[gakonst]

Nice start - we should also add a CI job for it

[mattsse]

Some parts work, however anything related to deploying and interacting hangs, could be due to misconfig on my end 🤷‍♂️ or the wasm package is too large.

Update

added wasm-pack example in examples/ethers-wasm.
Found the bug that prevented tx, and everything seems to work.
I ported the contract_with_abi example to ethers-wasm/tests.
To run it:

cd examples/ethers-wasm
yarn install
# start ganache in separate shell
yarn ganache
wasm-pack test --headless --firefox
# alternatively check in browser
yarn serve

This executes abigen, deploys the contract and sents tx, the test logs to console which should contain:

console.log div contained:
    starting
    deployed to 0xdcda…d7f2
    Value: hi. Logs: JsValue([Object({"author":"0xdad3bedb88f52b415a1aedf281213d8380747960","old_value":"","new_value":"initial value"}), Object({"author":"0xdad3bedb88f52b415a1aedf281213d8380747960","old_value":"initial value","new_value":"hi"})])

The two Websocket implementations are very similar and could probably easily be combined with some additional cfg's, based on #399

Unified both websocket implementations with only a few extra cfg's

[gakonst]

LGTM, follow ups from our discussion:

• Simplify the example, remove the need for webpack and make it as "vanilla" as possible
• NodeJS does not seem to be working right now. Unclear if it's a bug in how we do the WASM inside Rust, or if it's a config issue.

[gakonst]

This doesn't seem to be used anywhere?

[mattsse]

you're right, we don't actually use this directly, however we need to set this for it to compile standalone:
https://docs.rs/getrandom/0.2.3/getrandom/#indirect-dependencies