feat: updated forge.mjs and readme

Author: ioanatflowcrypt

extension/lib/README.md

@@ -6,20 +6,70 @@ Libraries that remain here verbatim are planned to use this mechanism in the fut
 
 Only add a copy of a library here if it's not published as a npm module.
 
-## How to update a non-minimzed forge.js
-1) Checkout the needed tag, e.g.
-```
-git clone -b v1.3.1 https://github.com/digitalbazaar/forge
+## How to update forge.js and forge.mjs
+
+Both `forge.js` and `forge.mjs` need to be rebuilt when updating node-forge to a new version.
+
+### 1) Clone the forge repository at the desired version
+
+```bash
+git clone -b v1.3.2 https://github.com/digitalbazaar/forge
 cd forge
 ```
 
-2) In `webpack.config.js` add a line `devtool: 'cheap-module-source-map'` for the plain unoptimized unminified bundle configuration similar to what there is in the optimized and minified bundle configuration.
+Replace `v1.3.2` with the desired version tag.
 
-3) Build the package
-```
-sudo apt install webpack
+### 2) Install dependencies
+
+```bash
 npm install
+```
+
+### 3) Build forge.js (UMD bundle with source maps)
+
+In `webpack.config.js`, add a line `devtool: 'cheap-module-source-map'` in the plain unoptimized unminified bundle configuration (around line 82), similar to what exists in the optimized bundle configuration.
+
+Then build:
+
+```bash
 npm run build
 ```
 
-4) A newly-generated `forge.js` should appear in `dist` subfolder, copy it over the file in this repo.
+Copy `dist/forge.js` to `extension/lib/forge.js` in this repository.
+
+### 4) Build forge.mjs (ES module)
+
+Install rollup and create a rollup configuration:
+
+```bash
+npm install --save-dev rollup @rollup/plugin-node-resolve @rollup/plugin-commonjs
+```
+
+Create `rollup.config.js`:
+
+```javascript
+import resolve from '@rollup/plugin-node-resolve';
+import commonjs from '@rollup/plugin-commonjs';
+
+export default {
+  input: 'lib/index.js',
+  output: {
+    file: 'dist/forge.mjs',
+    format: 'es',
+    sourcemap: true
+  },
+  plugins: [
+    resolve(),
+    commonjs()
+  ]
+};
+```
+
+Build the ES module:
+
+```bash
+npx rollup -c rollup.config.js
+```
+
+Copy `dist/forge.mjs` to `extension/lib/forge.mjs` in this repository.
+