I feel like I sound defensive every time I bring this up, but Angular supports three languages that are all equally first-class: JavaScript, TypeScript, and Dart[1].<p>Angular 2 is <i>written</i> in TypeScript because that felt that was the best source language to transpile <i>from</i>. But then they have transpile that to JS and Dart for users of those languages.<p>[1]: <a href="https:&#x2F;&#x2F;angular.io&#x2F;docs&#x2F;dart&#x2F;latest&#x2F;index.html" rel="nofollow">https:&#x2F;&#x2F;angular.io&#x2F;docs&#x2F;dart&#x2F;latest&#x2F;index.html</a>