Build process

[jacogr]

At least in the https://github.com/polkadot-js projects we need to support Browser/Node/React Native. wasm-pack is great, however the output options either creates something just for the browser or just for node.

Browser assumed webpack so does import * from 'schnorrkel_js_bg' - which is a WASM file, cannot be done on Node without webpack. The node output (--target nodejs) emits something where fs.readySync is used, once again, not quite usable in the Browser or RN.

Basically to get this working, I'm using the following scripts to support both environments.

build.sh -

#!/bin/sh

# install wasm-pack as required
if ! [ -x "$(command -v wasm-pack)" ]; then
  curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
fi

rm -rf ./pkg

rustup default nightly
wasm-pack build --target nodejs
rustup default stable

# make a backup of the original, use it, don't use it (useful for checking)
mv ./pkg/schnorrkel_js_bg.js ./pkg/schnorrkel_js_bg_node.js

./wasm2js.js

wasm2js.js -

#!/usr/bin/env node

const fs = require('fs');
const buffer = fs.readFileSync('./pkg/schnorrkel_js_bg.wasm');

fs.writeFileSync('./pkg/schnorrkel_js_bg.js', `const imports = {};\n
imports['./schnorrkel_js'] = require('./schnorrkel_js');\nconst bytes = Buffer.from('${buffer.toString('hex')}', 'hex');\nconst wasmModule = new WebAssembly.Module(bytes);\nconst wasmInstance = new WebAssembly.Instance(wasmModule, imports);\n\n
module.exports = wasmInstance.exports;`);

By far from the prettiest hack around, but it basically yields something that I can use as-is.

[kianenigma]

This is most likely fixed in this commit.

[jacogr]

Fixed, working, brilliant! (@parity/schnorrkel-js 0.1.2)