feat: adding options.configPath (#118)

* feat: adding options.root

So that koa-webpack can be further downstream than one hop from
mainModule while still maintaing some sane default functionality.

* docs: add configMap to options documentation

Also rename the option to "configMap" instead of "root".

* test(options): adding basic test for options.configPath

README.md

@@ -115,6 +115,26 @@ const middleware = await koaWebpack({ config });
 app.use(middleware);
 ```
 
+### configPath
+
+Type: `String`
+
+Allows you to specify the absolute path to the Webpack config file to be used.
+
+Example:
+
+```js
+const path = require('path');
+const koaWebpack = require('koa-webpack');
+
+// The Webpack config file would be at "./client/webpack.config.js".
+const middleware = await koaWebpack({
+  configPath: path.join(__dirname, 'client', 'webpack.config.js')
+});
+
+app.use(middleware);
+```
+
 ### devMiddleware
 
 Type: `Object`

lib/index.js

@@ -37,7 +37,7 @@ module.exports = async (opts) => {
   if (!compiler) {
     if (!config) {
       // eslint-disable-next-line import/no-dynamic-require, global-require
-      config = require(join(root.path, 'webpack.config.js'));
+      config = require(options.configPath || join(root.path, 'webpack.config.js'));
     }
 
     compiler = webpack(config);

lib/validate.js

@@ -10,13 +10,14 @@
 */
 const Joi = require('@hapi/joi');
 
-const { boolean, object, validate } = Joi.bind();
+const { string, boolean, object, validate } = Joi.bind();
 
 module.exports = {
   validate(options) {
     const keys = {
       compiler: [object().allow(null)],
       config: [object().allow(null)],
+      configPath: [string().allow(null)],
       devMiddleware: [object()],
       hotClient: [boolean(), object().allow(null)]
     };

test/fixtures/webpack.config.js

@@ -0,0 +1,10 @@
+const { resolve } = require('path');
+
+module.exports = {
+  mode: 'development',
+  entry: [resolve(__dirname, 'input.js')],
+  output: {
+    path: __dirname,
+    filename: 'output.js'
+  }
+};

test/test.js

@@ -9,16 +9,10 @@ const request = require('supertest');
 const webpack = require('webpack');
 
 const koaWebpack = require('../lib');
+const config = require('./fixtures/webpack.config');
 
 const defaults = {
-  config: {
-    mode: 'development',
-    entry: [resolve(__dirname, 'fixtures', 'input.js')],
-    output: {
-      path: resolve(__dirname, 'fixtures'),
-      filename: 'output.js'
-    }
-  },
+  config,
   devMiddleware: {
     publicPath: '/',
     logLevel: 'silent'
@@ -32,7 +26,7 @@ function buildOptions(opts) {
   const options = merge({}, defaults, opts);
   return merge(options, {
     config: null,
-    compiler: webpack(options.config)
+    ...opts.configPath ? {} : { compiler: webpack(options.config) }
   });
 }
 
@@ -163,3 +157,15 @@ test('continues on if the file is not part of webpack', async (t) => {
 
   return close(server, middleware);
 });
+
+test('uses supplied Webpack configuration file', async (t) => {
+  const { middleware, req, server } = await setup({
+    configPath: resolve(__dirname, 'fixtures', 'webpack.config.js')
+  });
+
+  const response = await req.get('/output.js').expect(200);
+
+  t.regex(response.text, /Hello World/);
+
+  return close(server, middleware);
+});