It is not that Dart language was not successful and in fact, it was a major success at Google and even the major teams in Google such as Google Fiber team, AdSense and AdWords are relying on it to develop consumer-facing web apps. It was also known that Dart is the fastest growing programming language at Google and that it indeed helps in providing 25 to 100 percent increase in the development speed.
Google is also coming up with a new project known as ‘Flutter’. Flutter is similar to that of Facebook’s React Native. By using single Dart codebase, developers will be able to write code for both the Android and iOS.