iOS 10 Release bundle errors

[grahamlyus]

Environment

System:
    OS: macOS Mojave 10.14.6
    CPU: (12) x64 Intel(R) Core(TM) i9-8950HK CPU @ 2.90GHz
    Memory: 1.38 GB / 32.00 GB
    Shell: 5.3 - /bin/zsh
  Binaries:
    Node: 12.11.0 - /var/folders/gk/9mp1z229013c3dl7p0wfcf500000gp/T/yarn--1588278802927-0.526041809933842/node
    Yarn: 1.19.1 - /var/folders/gk/9mp1z229013c3dl7p0wfcf500000gp/T/yarn--1588278802927-0.526041809933842/yarn
    npm: 6.11.3 - ~/.asdf/installs/nodejs/12.11.0/bin/npm
    Watchman: 4.1.0 - /usr/local/bin/watchman
  SDKs:
    iOS SDK:
      Platforms: iOS 13.4, DriverKit 19.0, macOS 10.15, tvOS 13.4, watchOS 6.2
    Android SDK:
      API Levels: 27, 28
      Build Tools: 28.0.3
      System Images: android-21 | Google APIs Intel x86 Atom_64, android-23 | Google APIs Intel x86 Atom, android-27 | Intel x86 Atom_64, android-27 | Google APIs Intel x86 Atom, android-28 | Google APIs Intel x86 Atom, android-29 | Google APIs Intel x86 Atom, android-29 | Google Play Intel x86 Atom
  IDEs:
    Xcode: 11.4/11N123k - /usr/bin/xcodebuild
  npmPackages:
    react: 16.9.0 => 16.9.0
    react-native: 0.61.5 => 0.61.5

  "dependencies": {
    "react": "16.9.0",
    "react-native": "0.61.5"
  },
  "devDependencies": {
    "@babel/core": "^7.6.2",
    "@babel/runtime": "^7.6.2",
    "@haul-bundler/babel-preset-react-native": "^0.16.0",
    "@haul-bundler/cli": "^0.20.0",
    "@haul-bundler/preset-0.60": "^0.18.0",
    "@react-native-community/eslint-config": "^0.0.5",
    "babel-jest": "^24.9.0",
    "eslint": "^6.5.1",
    "jest": "^24.9.0",
    "metro-react-native-babel-preset": "^0.56.0",
    "react-test-renderer": "16.9.0"
  },

Description

Related issues #636, #685.

Running release bundle fails on iOS 10 and causes a crash at launch. There are 2 problems:

Unhandled JS Exception: Unexpected token '...'. Expected a property name.

The spread operator is not being transformed. Fixed by adding

plugins: ['@babel/plugin-proposal-object-rest-spread'],

to my babel.config.js

Unhandled JS Exception: Cannot declare a const variable twice: 'e'.

Sometimes it'll be let instead of const. Fixed by adding minifyOptions to haul.config.js:

import { withPolyfills, makeConfig } from "@haul-bundler/preset-0.60";

export default makeConfig({
  bundles: {
    index: {
      entry: withPolyfills('./index'),
      minifyOptions: {
        safari10: true,
      },
    },
  },
});

However, it also needs a patch as the minifyOptions are not being passed thru to terser-webpack-plugin:

diff --git a/node_modules/@haul-bundler/preset-0.60/build/defaultConfig.js b/node_modules/@haul-bundler/preset-0.60/build/defaultConfig.js
index 76131e9..f913f45 100644
--- a/node_modules/@haul-bundler/preset-0.60/build/defaultConfig.js
+++ b/node_modules/@haul-bundler/preset-0.60/build/defaultConfig.js
@@ -31,6 +31,7 @@ function getDefaultConfig(runtime, env, bundleName, projectConfig) {
     assetsDest,
     dev,
     minify,
+    minifyOptions,
     providesModuleNodeModules,
     hasteOptions,
     maxWorkers,
@@ -163,7 +164,8 @@ function getDefaultConfig(runtime, env, bundleName, projectConfig) {
         cache: true,
         // Set upper limit on CPU cores, to prevent Out of Memory exception on CIs.
         parallel: _isCi.default ? Math.min(_os.default.cpus().length, 8) - 1 : true,
-        sourceMap: true
+        sourceMap: true,
+        terserOptions: minifyOptions || {}
       })] : [],
       namedModules: dev,
       concatenateModules: true

Reproducible Demo

Create new project and add haul

npx react-native init MyProject --version "0.61.5"
cd MyProject
yarn add --dev @haul-bundler/cli
yarn haul init

Open ios/MyProject.xcworkspace in Xcode

Product > Scheme > Edit Scheme and change Build Configuration to Release

Select a simulator running iOS 10 (e.g. iPad Pro (9.7-inch) -- 10.3.1)

Build and Run (see Description above)

Vanilla React Native supports iOS 10, so I think Haul should also. Thoughts?