I agree that something possibly dangerous should be harder to mis-use. The world is full of small oversights. Having said that, surely this is the job of a lint

I agree that something possibly dangerous should be harder to mis-use. The world is full of small oversights. Having said that, surely this is the job of a linter - does one exist for mustache? I've never seen JSX before (I haven't learned anything new in front-end later than ES5). In your example, it looks more like an attribute than an inner tag, the former of which I'd almost always escape. Is that how you set inner HTML as well?