[EXPO] iOS Build Settings

An Expo Config Plugin that lets you set arbitrary iOS build settings directly from your app.config.js / app.config.ts.

Why?

Expo's managed workflow abstracts away the native Xcode project, but some libraries or deployment requirements need specific entries in the build settings (e.g. SWIFT_VERSION, OTHER_LDFLAGS, ENABLE_BITCODE, custom preprocessor macros, etc.). Rather than ejecting or maintaining a custom prebuild script, this plugin patches every build configuration in your .xcodeproj at prebuild time.

Installation

npm install with-build-settings
# or
yarn add with-build-settings

Usage

Add the plugin to your app.config.js or app.config.ts and pass the build settings you want to inject as key-value pairs:

// app.config.js
export default {
  plugins: [
    [
      "@leko/expo-ios-build-settings",
      {
        SWIFT_VERSION: "5.0",
        ENABLE_BITCODE: "NO",
        OTHER_LDFLAGS: "$(inherited) -ObjC",
      },
    ],
  ],
};

Then run prebuild to apply the changes:

npx expo prebuild --platform ios

Configuration

The plugin accepts a plain object — any key-value pair that is valid in an Xcode build configuration block.

| Key | Type | Description | | --------------------- | -------- | ------------------------------------------------ | | [BUILD_SETTING_KEY] | string | Any valid Xcode build setting name and its value |

Common examples

| Setting | Example value | Purpose | | ------------------------------ | -------------------------- | --------------------------------------- | | SWIFT_VERSION | "5.0" | Set the Swift language version | | ENABLE_BITCODE | "NO" | Disable Bitcode (required by some SDKs) | | GCC_PREPROCESSOR_DEFINITIONS | "$(inherited) MY_FLAG=1" | Inject preprocessor macros | | OTHER_LDFLAGS | "$(inherited) -ObjC" | Append linker flags | | IPHONEOS_DEPLOYMENT_TARGET | "14.0" | Override the minimum iOS version |

How it works

The plugin uses withXcodeProject from @expo/config-plugins to access the parsed .xcodeproj at prebuild time. It then iterates over every entry in pbxXCBuildConfigurationSection() — which covers both Debug and Release configurations — and writes the provided key-value pairs into each configuration's buildSettings object.

app.config.js  ──►  withBuildSettings  ──►  withXcodeProject  ──►  .xcodeproj
                    (your key/values)        (Expo mod system)     buildSettings{}

Note: Settings are applied to all build configurations (Debug, Release, and any custom ones).

Requirements

• Expo SDK 47+
• @expo/config-plugins (included transitively with Expo)

License

MIT