feat: add next plugin that deals with webpack workarounds

The canvas package, which is a dependency of jsdom, has a native binding which causes the following error during Next.js build process: "Module did not self-register".
We circuvent that by using a null-loader.
See vercel/next.js#7894

The ws package, which is also a dependency of jsdom, tries to optionally load some dependencies.
This produces a warning in webpack that we want to avoid.
We circuvent that by adding them to externals.

README.md

@@ -29,7 +29,17 @@ All the polyfilling will be taken care by this library automatically, so that yo
 
 ## Setup
 
-#### 1. Create a root folder named `intl` with the following structure:
+#### 1 Add the plugin to your `next.config.js`
+
+```js
+const withNextIntl = require('@moxy/next-intl/plugin');
+
+module.exports = withNextIntl()({ ...nextConfig });
+```
+
+This plugin will make some [modifications](src/plugin.js) to your webpack config to circuvent a few issues related to JSDOM, which is a runtime dependency of `react-intl` for the server.
+
+#### 2. Create a root folder named `intl` with the following structure:
 
 ```
 intl/
@@ -71,7 +81,7 @@ The `messages/en-US.json` file contains the messages for the `en-US` locale:
 }
 ```
 
-#### 2. Include `<NextIntlScript>` in `pages/_document.js`:
+#### 3. Include `<NextIntlScript>` in `pages/_document.js`:
 
 ```js
 import React from 'react';
@@ -96,7 +106,7 @@ export default class MyDocument extends Document {
 }
 ```
 
-#### 3. Wrap your app with `withNextIntlSetup` in `pages/_app.js`:
+#### 4. Wrap your app with `withNextIntlSetup` in `pages/_app.js`:
 
 ```js
 import React from 'react';
@@ -131,7 +141,7 @@ class MyApp extends App {
 export default withNextIntlSetup(nextIntlConfig)(MyApp);
 ```
 
-#### 4. Ready!
+#### 5. Ready!
 
 You may now use [`react-intl`](https://www.npmjs.com/package/react-intl) as you normally would. Moreover, you will receive the current locale in your pages' `getInitialProps` static function.
 

package.json

@@ -50,6 +50,7 @@
     "hoist-non-react-statics": "^3.3.1",
     "jsdom": "^15.2.1",
     "memoize-one": "^5.1.1",
+    "null-loader": "^3.0.0",
     "p-cancelable": "^2.0.0",
     "pico-signals": "^1.0.0",
     "prop-types": "^15.7.2",
@@ -66,7 +67,6 @@
     "@commitlint/config-conventional": "^8.1.0",
     "@moxy/jest-config": "^1.1.0",
     "@testing-library/react": "^9.3.2",
-    "babel-jest": "^24.9.0",
     "babel-preset-moxy": "^3.2.0",
     "delay": "^4.3.0",
     "eslint": "^6.6.0",

plugin.js

@@ -0,0 +1,3 @@
+/* eslint-disable prefer-import/prefer-import-over-require */
+
+module.exports = require('./lib/plugin');

src/plugin.js

@@ -0,0 +1,41 @@
+const castArray = (value) => {
+    if (Array.isArray(value)) {
+        return value;
+    }
+
+    return value != null ? [value] : [];
+};
+
+const withNextIntl = () => (nextConfig = {}) => ({
+    ...nextConfig,
+    webpack: (config, options) => {
+        const { isServer } = options;
+
+        if (isServer) {
+            // The canvas package, which is a dependency of jsdom, has a native binding which causes
+            // the following error during Next.js build process: "Module did not self-register"
+            // See https://github.com/zeit/next.js/issues/7894
+            // We circuvent that by using a null-loader
+            config.module.rules.unshift({
+                test: require.resolve('canvas'),
+                loader: require.resolve('null-loader'),
+            });
+
+            // The ws package, which is also a dependency of jsdom, tries to optionally load some dependencies
+            // This produces a warning in webpack that we want to avoid
+            config.externals = [
+                'bufferutil',
+                'utf-8-validate',
+                ...castArray(config.externals),
+            ];
+        }
+
+        if (typeof nextConfig.webpack === 'function') {
+            return nextConfig.webpack(config, options);
+        }
+
+        return config;
+    },
+});
+
+export default withNextIntl;

src/plugin.test.js

@@ -0,0 +1,47 @@
+const nextIntlPlugin = require('./plugin');
+
+const webpackOptions = {
+    isServer: true,
+};
+
+const createWebpackConfig = () => ({
+    module: {
+        rules: [
+            {
+                test: 'foo',
+                loader: 'foo-loader',
+            },
+        ],
+    },
+    externals: () => {},
+});
+
+it('should add a rule for canvas that uses null-loader', () => {
+    const config = nextIntlPlugin()().webpack(createWebpackConfig(), webpackOptions);
+
+    const rule = config.module.rules[0];
+
+    expect(rule.test).toBe(require.resolve('canvas'));
+    expect(rule.loader).toBe(require.resolve('null-loader'));
+});
+
+it('should add no canvas rule when not server', () => {
+    const config = nextIntlPlugin()().webpack(createWebpackConfig(), { ...webpackOptions, isServer: false });
+
+    expect(config.module.rules[0].test).toBe('foo');
+});
+
+it('should add ws\'s optional dependencies to externals', () => {
+    const config = nextIntlPlugin()().webpack(createWebpackConfig(), webpackOptions);
+
+    expect(config.externals).toHaveLength(3);
+    expect(config.externals[0]).toBe('bufferutil');
+    expect(config.externals[1]).toBe('utf-8-validate');
+    expect(typeof config.externals[2]).toBe('function');
+});
+
+it('should leave externals untouched when not server', () => {
+    const config = nextIntlPlugin()().webpack(createWebpackConfig(), { ...webpackOptions, isServer: false });
+
+    expect(typeof config.externals).toBe('function');
+});