Add resolve support for .js and .jsx files

config/webpack/index.js

@@ -4,6 +4,7 @@ require( './module.js' );
 require( './plugins.js' );
 require( './devtool.js' );
 require( './externals.js' );
+require( './resolve.js' );
 
 const { webpack } = require('./config');
 

config/webpack/resolve.js

@@ -0,0 +1,9 @@
+const { webpack } = require('./config');
+
+webpack.setProp('resolve', function () {
+  this.config.resolve = {
+    extensions: ['.js', '.jsx']
+  }
+});
+
+module.exports = { webpack };

config/webpack/tests/resolve.test.js

@@ -0,0 +1,19 @@
+const assert = require('chai').assert;
+const _resolve = require('../resolve');
+const { webpack } = require('../config');
+
+describe( 'resolve', function() {
+  describe( 'props', function ( ) {
+    it( 'should define a resolve property', function () {
+      assert.property( webpack.config, 'resolve' );
+    } );
+
+    it( 'should be of type object', function () {
+      assert.isObject( webpack.config.resolve );
+    } );
+
+    it( 'should contain a extensions array', function () {
+      assert.isArray( webpack.config.resolve.extensions );
+    } );
+  } );
+} );