Support Webpack 4 (e.g. for Create React App)

[webmaster128]

When trying to use this lib from npm in a React project, I get the error

Failed to compile.

./node_modules/drand-client/verifying.js 16:29
Module parse failed: Unexpected token (16:29)
File was processed with these loaders:
 * ./node_modules/react-scripts/node_modules/babel-loader/lib/index.js
You may need an additional loader to handle the result of these loaders.
|         // TODO: switch to TinyGo when math/big works for smaller wasm file and non-global exports.
|         const go = new Go();
>         const url = `${import.meta.url.split('/').slice(0, -1).join('/')}/wasm/drand.wasm`;
|         let result;
|

This is because import.meta.url is not supported in Webpack 4. Webpack 5 support probably will take some more time.

I have no great idea how to solve this, but let's see.

[webmaster128]

Starting with Webpack 5, import.meta.url is resolved to an absolute file URL at build time. Then

        // TODO: switch to TinyGo when math/big works for smaller wasm file and non-global exports.
        const go = new Go()
        const url = `${import.meta.url.split('/').slice(0, -1).join('/')}/wasm/drand.wasm`
        let result

becomes

// TODO: switch to TinyGo when math/big works for smaller wasm file and non-global exports.
const go = new Go()
const url = `${"file:///Users/me/projects/drand-client/verifying.js".split('/').slice(0, -1).join('/')}/wasm/drand.wasm`
let result

which is not very helpful. However, a small rewrite to

        // TODO: switch to TinyGo when math/big works for smaller wasm file and non-global exports.
        const go = new Go()
        const url = new URL("./wasm/drand.wasm", import.meta.url)
        let result

lets Webpack bundle the Wasm file as an asset.

[CluEleSsUK]

The client has now been migrated to typescript, so you shouldn't have a problem with create-react-app as there's no wasm binding! Let me know if you have any issues