Add Swift Package Manager (SPM) support for iOS

[wytzepiet]

Swift Package Manager support needed

Flutter is migrating from CocoaPods to Swift Package Manager (SPM) for managing iOS and macOS native dependencies. Currently, flutter_js does not include a Package.swift manifest, which causes the following warning during builds:

The following plugins do not support Swift Package Manager for ios:
  - flutter_js
This will become an error in a future version of Flutter.

Why this matters

• CocoaPods is now in maintenance mode — SPM is Flutter's actively supported path forward for iOS native dependencies.
• This warning will become a build error in a future Flutter version, breaking iOS builds for all flutter_js users.
• SPM is bundled with Xcode, removing the need for a separate Ruby/CocoaPods installation.

What needs to be done

The Flutter team has published a migration guide for plugin authors:
👉 https://docs.flutter.dev/packages-and-plugins/swift-package-manager/for-plugin-authors#how-to-add-swift-package-manager-support-to-an-existing-flutter-plugin

In short, this involves adding a Package.swift to the ios/ directory of the plugin alongside the existing flutter_js.podspec, so both CocoaPods and SPM are supported during the transition period.

References

• Flutter SPM migration tracking issue: flutter/flutter#126005
• Flutter docs for plugin authors: https://docs.flutter.dev/packages-and-plugins/swift-package-manager/for-plugin-authors

Thank you for maintaining this plugin — it's widely used and keeping it forward-compatible would be much appreciated! Happy to help test if needed.