When comparing React Native vs Flutter, the Slant community recommends Flutter for most people. In the question“What are the best tools for making a cross-platform application?” Flutter is ranked 7th while React Native is ranked 12th.
Ranked in these QuestionsQuestion Ranking
Pro Allows you to develop native apps
Pro Large, supportive community
Despite being such a young framework (early 2015), the support for React Native grew quickly. There is a forum, active tag on Stackoverflow and many other ways to get help from the community.
Pro Backed by Facebook
Facebook writes their mobile apps in React Native so the code base gets pretty thoroughly used in some highly demanding scenarios.
Pro More predictable control of the state
The one way data flow, makes it more predictable and easy to control.
Pro Open source
Pro Great developer tools debug/hotreload/analyser
Pro Based on Dart language
Dart is a Java like language, easy to learn and startup fast for millions of Java developers.
Pro A single codebase for iOS AND Android
The developer's goal is to allow people to make apps running at 120 FPS.
Con If core team doesn't use a certain feature, it's not developed
Whenever there's functionality you need that they don't use in their apps, it's not going to get developed by them, even if it's obvious it should be in the core. They always say to either submit a PR or create a separate module.
Con Steep learning curve
Con Many existing JS libraries are not usable on React Native; not exactly a 1-to-1 experience to writing React either
Example: Library that provides a full calendar with agenda view.
Con React native only supports react which is getting old
React native is only based on react which is getting old. An old tech developer can't take much breaking changes so it gets more patchs. There is a limit, and react is too verbose and complex. better alternatives available today.
Con Still in development
According to the website, Flutter is still in its early stages of development.
Con Based on Dart language
Dart is a Java like language, easy to learn and startup fast for millions of Java developers. BUT if you have to learn it ... it's a con.
Con Dart is unpopular and never gained serious community traction like Kotlin or Java
Con Does not support 32-bit iOS devices
If you plan on targeting iPhone 5, 5C or earlier, you can forget about Flutter.