TypeScript is older. It was first released in 2012, whereas Dart was released in 2013.<p>Dart arrived with much fanfare though, whereas TypeScript was more low-key, and it&#x27;s taken a while to become mainstream. Google&#x27;s announcement that Angular 2 would use it has brought it a lot more attention from outside of the traditional MS&#x2F;.NET dev crowd.<p>Microsoft have also been shifting the project&#x27;s focus towards a more Babel-esque one, emphasising greater interoperability with existing (untyped) JS libraries, and support for new ES6&#x2F;2015 features (and beyond).