From cc8ec49ca0d91ae821ea3d1cc7bd45a49d56b9aa Mon Sep 17 00:00:00 2001
From: Mathias Biilmann Christensen <info@mathias-biilmann.net>
Date: Fri, 5 Jan 2018 18:47:01 -0800
Subject: [PATCH] Support for customizing babel and webpack

This makes netlify-lambda respect any .babelrc in the folder it runs from
It also adds a -c <config> flag for passing an additional webpack config
to the build or serve command
---
 README.md    |  8 ++++++++
 bin/cmd.js   |  7 +++++--
 lib/build.js | 35 ++++++++++++++++++++++-------------
 package.json |  3 ++-
 yarn.lock    |  6 ++++++
 5 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index f8b6b671..937a4fde 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,14 @@ http://localhost:9000/hello -> folder/hello.js (must export a handler(event, con
 
 The `build` function will run a single build of the functions in the folder.
 
+## Webpack Configuration
+
+By default the webpack configuration uses `babel-loader` to load all js files. Any `.babelrc` in the directory `netlify-lambda` is run from will be respected. If no `.babelrc` is found, a few basic settings are used.
+
+If you need to use additional webpack modules or loaders, you can specify an additional webpack config with the `-c` option when running either `serve` or `build`.
+
+The additional webpack config will be merged into the default config via [webpack-merge's](https://www.npmjs.com/package/webpack-merge) `merge.smart` method.
+
 ## License
 
 [MIT](LICENSE)
\ No newline at end of file
diff --git a/bin/cmd.js b/bin/cmd.js
index ab372c8d..e473a769 100755
--- a/bin/cmd.js
+++ b/bin/cmd.js
@@ -15,13 +15,16 @@ var serve = require("../lib/serve");
 
 program.version(pkg.version);
 
+program
+  .option("-c --config <webpack-config>", "additional webpack configuration")
+
 program
   .command("serve <dir>")
   .description("serve and watch functions")
   .action(function(cmd, options) {
     console.log("Starting server");
     var server = serve.listen(9000);
-    build.watch(cmd, function(err, stats) {
+    build.watch(cmd, program.config, function(err, stats) {
       if (err) {
         console.error(err);
         return;
@@ -41,7 +44,7 @@ program
   .action(function(cmd, options) {
     console.log("Building functions");
     build
-      .run(cmd)
+      .run(cmd, program.config)
       .then(function(stats) {
         console.log(stats.toString({ color: true }));
       })
diff --git a/lib/build.js b/lib/build.js
index eae2f2e2..307a06a4 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -2,9 +2,20 @@ var fs = require("fs");
 var path = require("path");
 var conf = require("./config");
 var webpack = require("webpack");
+var merge = require("webpack-merge");
 
-function webpackConfig(dir) {
+function webpackConfig(dir, additionalConfig) {
   var config = conf.load();
+  var babelOpts = {cacheDirectory: true};
+  if (!fs.existsSync(path.join(process.cwd(), '.babelrc'))) {
+    babelOpts.presets = ["es2015"];
+    babelOptsplugins = [
+      "transform-class-properties",
+      "transform-object-assign",
+      "transform-object-rest-spread"
+    ];
+  }
+
   var webpackConfig = {
     module: {
       rules: [
@@ -13,15 +24,7 @@ function webpackConfig(dir) {
           exclude: /(node_modules|bower_components)/,
           use: {
             loader: "babel-loader",
-            options: {
-              cacheDirectory: true,
-              presets: ["es2015"],
-              plugins: [
-                "transform-class-properties",
-                "transform-object-assign",
-                "transform-object-rest-spread"
-              ]
-            }
+            options: babelOpts
           }
         }
       ]
@@ -46,12 +49,18 @@ function webpackConfig(dir) {
       webpackConfig.entry[name] = "./" + name;
     }
   });
+  if (additionalConfig) {
+    var webpackAdditional = require(path.join(process.cwd(), additionalConfig));
+
+    return merge.smart(webpackConfig, webpackAdditional);
+  }
+
   return webpackConfig;
 }
 
-exports.run = function(dir) {
+exports.run = function(dir, additionalConfig) {
   return new Promise(function(resolve, reject) {
-    webpack(webpackConfig(dir), function(err, stats) {
+    webpack(webpackConfig(dir, additionalConfig), function(err, stats) {
       if (err) {
         return reject(err);
       }
@@ -60,7 +69,7 @@ exports.run = function(dir) {
   });
 };
 
-exports.watch = function(dir, cb) {
+exports.watch = function(dir, additionalConfig, cb) {
   var compiler = webpack(webpackConfig(dir));
   compiler.watch(webpackConfig(dir), cb);
 };
diff --git a/package.json b/package.json
index 1ab81c41..a07bd441 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "express": "^4.16.2",
     "express-logging": "^1.1.1",
     "toml": "^2.3.3",
-    "webpack": "^3.8.1"
+    "webpack": "^3.8.1",
+    "webpack-merge": "^4.1.1"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 56e841b4..5113b6b4 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2791,6 +2791,12 @@ watchpack@^1.4.0:
     chokidar "^1.7.0"
     graceful-fs "^4.1.2"
 
+webpack-merge@^4.1.1:
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-4.1.1.tgz#f1197a0a973e69c6fbeeb6d658219aa8c0c13555"
+  dependencies:
+    lodash "^4.17.4"
+
 webpack-sources@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/webpack-sources/-/webpack-sources-1.0.2.tgz#d0148ec083b3b5ccef1035a6b3ec16442983b27a"