https://rnfirebase.io/#3-ios-setup

🔥 아래처럼 따라하시면 동작합니다!!

1. 'GoogleService-Info.plist' 파일은 ios 폴더 아래에 넣습니다.
2. 추가 설정은 아래 두 파일의 "for Firebase"라고 표시된 부분을 복붙해 넣으십시오.
3. 안되면 댓글 달아주세요.

# <filename: ios/Podfile>
require_relative '../node_modules/react-native/scripts/react_native_pods'
require_relative '../node_modules/@react-native-community/cli-platform-ios/native_modules'

platform :ios, min_ios_version_supported
prepare_react_native_project!

# If you are using a `react-native-flipper` your iOS build will fail when `NO_FLIPPER=1` is set.
# because `react-native-flipper` depends on (FlipperKit,...) that will be excluded
#
# To fix this you can also exclude `react-native-flipper` using a `react-native.config.js`
# ```js
# module.exports = {
#   dependencies: {
#     ...(process.env.NO_FLIPPER ? { 'react-native-flipper': { platforms: { ios: null } } } : {}),
# ```
flipper_config = ENV['NO_FLIPPER'] == "1" ? FlipperConfiguration.disabled : FlipperConfiguration.enabled

linkage = ENV['USE_FRAMEWORKS']
if linkage != nil
  Pod::UI.puts "Configuring Pod with #{linkage}ally linked Frameworks".green
  use_frameworks! :linkage => linkage.to_sym
end

target 'RNFB' do
  config = use_native_modules!
  use_frameworks! :linkage => :static # for Firebase
  $RNFirebaseAsStaticFramework = true # for Firebase

  # Flags change depending on the env values.
  flags = get_default_flags()

  use_react_native!(
    :path => config[:reactNativePath],
    # Hermes is now enabled by default. Disable by setting this flag to false.
    # Upcoming versions of React Native may rely on get_default_flags(), but
    # we make it explicit here to aid in the React Native upgrade process.
    :hermes_enabled => flags[:hermes_enabled],
    :fabric_enabled => flags[:fabric_enabled],
    # Enables Flipper.
    #
    # Note that if you have use_frameworks! enabled, Flipper will not work and
    # you should disable the next line.
    # :flipper_configuration => flipper_config, # for Firebase
    # An absolute path to your application root.
    :app_path => "#{Pod::Config.instance.installation_root}/.."
  )

  $FirebaseSDKVersion = '10.4.0' # for Firebase
  target 'RNFBTests' do
    inherit! :complete
    # Pods for testing
  end

  post_install do |installer|
    react_native_post_install(
      installer,
      # Set `mac_catalyst_enabled` to `true` in order to apply patches
      # necessary for Mac Catalyst builds
      :mac_catalyst_enabled => false
    )
    __apply_Xcode_12_5_M1_post_install_workaround(installer)

    # for Firebase (all below)
    installer.pods_project.targets.each do |target|
      target.build_configurations.each do |config|
        config.build_settings["GCC_WARN_INHIBIT_ALL_WARNINGS"] = "YES"
      end
    end
    
    installer.pods_project.targets.each do |target|
      target.build_configurations.each do |config|
        config.build_settings["CC"] = "clang"
        config.build_settings["LD"] = "clang"
        config.build_settings["CXX"] = "clang++"
        config.build_settings["LDPLUSPLUS"] = "clang++"
      end
    end
    
    installer.aggregate_targets.each do |aggregate_target|
      aggregate_target.user_project.native_targets.each do |target|
        target.build_configurations.each do |config|
          config.build_settings['ONLY_ACTIVE_ARCH'] = 'YES'
          config.build_settings['EXCLUDED_ARCHS'] = 'i386'
        end
      end
      aggregate_target.user_project.save
    end
    installer.pods_project.targets.each do |target|
      if (target.name.eql?('FBReactNativeSpec'))
        target.build_phases.each do |build_phase|
          if (build_phase.respond_to?(:name) && build_phase.name.eql?('[CP-User] Generate Specs'))
            target.build_phases.move(build_phase, 0)
          end
        end
      end
    end
    
    installer.pods_project.targets.each do |target|
      target.build_configurations.each do |config|
        config.build_settings["ENABLE_BITCODE"] = "NO"
      end
    end
  end
end

// <filename: ios/[project name]/AppDelegate.mm>
#import "AppDelegate.h"
#import <Firebase.h> // for Firebase

#import <React/RCTBundleURLProvider.h>

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  if ([FIRApp defaultApp] == nil) { [FIRApp configure]; } // for Firebase
  self.moduleName = @"RNFB";
  // You can add your custom initial props in the dictionary below.
  // They will be passed down to the ViewController used by React Native.
  self.initialProps = @{};

  return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

- (NSURL *)sourceURLForBridge:(RCTBridge *)bridge
{
#if DEBUG
  return [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index"];
#else
  return [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
#endif
}

/// This method controls whether the `concurrentRoot`feature of React18 is turned on or off.
///
/// @see: https://reactjs.org/blog/2022/03/29/react-v18.html
/// @note: This requires to be rendering on Fabric (i.e. on the New Architecture).
/// @return: `true` if the `concurrentRoot` feature is enabled. Otherwise, it returns `false`.
- (BOOL)concurrentRootEnabled
{
  return true;
}

@end