From 345c15d9fed45f3184ef431fadec6e9bb6ec69fd Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Fri, 19 Aug 2022 09:37:17 -0700
Subject: [PATCH] chore: code style parity with locker (#377)

---
 scripts/rollup/configs/base.cjs         | 13 +++++++++----
 scripts/rollup/plugins/babel-output.cjs | 24 +++++++++++++-----------
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/scripts/rollup/configs/base.cjs b/scripts/rollup/configs/base.cjs
index a6162b44..8ce72d5d 100644
--- a/scripts/rollup/configs/base.cjs
+++ b/scripts/rollup/configs/base.cjs
@@ -4,6 +4,11 @@ const mergeOptions = require('merge-options');
 const typescriptPlugin = require('@rollup/plugin-typescript');
 const { getBabelOutputPlugin } = require('../plugins/babel-output.cjs');
 
+const mergeOptionsConfig = {
+    concatArrays: true,
+    ignoreUndefined: true,
+};
+
 function createConfig({
     // prettier-ignore
     input = 'src/index.ts',
@@ -13,7 +18,7 @@ function createConfig({
     const isCJS = format === 'cjs';
 
     return mergeOptions.call(
-        { concatArrays: true },
+        mergeOptionsConfig,
         {
             input,
             external: [],
@@ -36,10 +41,10 @@ function createConfig({
 }
 
 module.exports = {
-    rollupConfig(options = {}) {
+    rollupConfig(providedOptions) {
         return [
-            createConfig({ ...options, format: 'es' }),
-            createConfig({ ...options, format: 'cjs' }),
+            createConfig({ ...providedOptions, format: 'es' }),
+            createConfig({ ...providedOptions, format: 'cjs' }),
         ];
     },
 };
diff --git a/scripts/rollup/plugins/babel-output.cjs b/scripts/rollup/plugins/babel-output.cjs
index bb1c1804..7e8cf3f0 100644
--- a/scripts/rollup/plugins/babel-output.cjs
+++ b/scripts/rollup/plugins/babel-output.cjs
@@ -8,15 +8,16 @@ const path = require('path');
 
 const rootPath = path.resolve(__dirname, '../../../');
 
+const mergeOptionsConfig = {
+    ignoreUndefined: true,
+};
+
 module.exports = {
-    getBabelOutputPlugin(providedOptions = {}) {
-        const options = {
-            __proto__: null,
-            ...providedOptions,
-        };
-        const { banner, footer } = options;
-        delete options.banner;
-        delete options.footer;
+    getBabelOutputPlugin(providedOptions) {
+        const clonedOptions = { ...providedOptions };
+        const { banner, footer } = clonedOptions;
+        delete clonedOptions.banner;
+        delete clonedOptions.footer;
         let babelOutputHooks;
         return {
             name: 'babel-output',
@@ -31,14 +32,15 @@ module.exports = {
                     // https://github.com/babel/babel/blob/v7.15.6/packages/babel-core/src/config/files/configuration.ts#L24
                     const configPath =
                         // prettier-ignore
-                        options.configFile ??
+                        clonedOptions.configFile ??
                         (await globby([`${path.resolve('.babelrc')}{,.js,.cjs,.mjs,.json}`]))[0] ??
                         (await globby([`${path.resolve(rootPath, 'babel.config')}{.js,.cjs,.mjs,.json}`]))[0];
                     const config =
                         path.extname(configPath) === '.json'
                             ? await fs.readJSON(configPath)
                             : (await import(configPath)).default;
-                    const mergedOptions = mergeOptions(
+                    const mergedOptions = mergeOptions.call(
+                        mergeOptionsConfig,
                         {
                             allowAllFormats: true,
                             babelrc: false,
@@ -47,7 +49,7 @@ module.exports = {
                             presets: [],
                         },
                         config,
-                        options,
+                        clonedOptions,
                         {
                             configFile: false,
                         }