I bet we'll be seeing a lot more of Typescript in the next few years, seeing as it's the default language that is suggested in Angular 2's documentation. I find it odd that Dart wasn't the default language of choice for Angular 2 (although it is fully supported) seeing as Google is behind both projects. I think it really boils down to what the author wrote here: "Dart is not JavaScript. TypeScript is." At the end of the day more people are going to want to use what they are already more familiar with, and it's really not necessary to throw out years and years of progress we have made on JS.