Revert back to old commonjs behaviour.

A recent dependency update changed the exported values in our commonjs
entries by exposing both the default export and named exports. This
commit ensures that we're always using the default export and ignore any
named ones.

Author: marvinhagemeister

config/node-commonjs.js

@@ -0,0 +1,21 @@
+const fs = require('fs');
+const path = require('path');
+
+// This file will only export default exports in commonjs bundles
+// instead of guarding them behind a `.default` property.
+
+const filePath = (file) => path.join(process.cwd(), 'dist', file);
+
+// Main entry
+fs.copyFileSync(filePath('index.js'), filePath('commonjs.js'));
+fs.copyFileSync(filePath('index.js.map'), filePath('commonjs.js.map'));
+
+const source = `module.exports = require('./commonjs').default;`;
+fs.writeFileSync(filePath('index.js'), source, 'utf-8');
+
+// JSX entry
+fs.copyFileSync(filePath('jsx.js'), filePath('jsx-entry.js'));
+fs.copyFileSync(filePath('jsx.js.map'), filePath('jsx-entry.js.map'));
+
+const sourceJsx = `module.exports = require('./jsx-entry').default;`;
+fs.writeFileSync(filePath('jsx.js'), sourceJsx, 'utf-8');

package.json

@@ -23,7 +23,7 @@
 	},
 	"scripts": {
 		"build": "npm run -s transpile && npm run -s transpile:jsx && npm run -s copy-typescript-definition",
-		"postbuild": "node ./config/node-13-exports.js",
+		"postbuild": "node ./config/node-13-exports.js && node ./config/node-commonjs.js",
 		"transpile": "microbundle src/index.js -f es,umd --target web --external preact",
 		"transpile:jsx": "microbundle src/jsx.js -o dist/jsx.js --target web --external none && microbundle dist/jsx.js -o dist/jsx.js -f cjs",
 		"copy-typescript-definition": "copyfiles -f src/*.d.ts dist",