[couchand]

I don't think any of them are very polished or professional.

The CoffeeScript site reports errors unintuitively yet visibly in the top-right corner. The TypeScript site requires that you scroll right to the error and then realize it's not just your browser complaining about a misspelling. But both are better than the Dart sandbox, which basically only says "error".

None of them get page layout right. Dart and TypeScript have obvious input/output boxes, but both get demerits for their handling of overflow. Dart just grows the box which is acceptable, but TypeScript thinks their customized scroll bars are better than native. CoffeeScript handles overflow reasonably, but it's a big translucent overlay causing all sorts of moire on my screen.

I suppose if you're on a Windows computer you might be tricked into thinking the TypeScript page looks reasonable, since it probably fits in. For me, though, I'm having a hell of a time figuring out what's a button and what's not.

[bilalhusain]

I hope the respective developers are listening. It should be noted that most of these 'try X' editors are not marketed as a product, but I do agree that calling it 'professional' was mistake. The warts show up during heavy usage of a tool (the overflow example) and I was quick to reach conclusions based on the first impressions. But all the features like completion, line numbers, syntax highlighting do deserve respect (I couldn't find a better executed alternative!).

Also, confirming that I am on a Windows computer :)

[xixixao]

The Try it for CoffeeScript was meant to be extremely simple, not to replace JSFiddle and such. The errors will be moved to the output area in next release. Someone might get around to implementing proper editor into it (say CodeMirror). That said, MS has people they pay for developing TypeScript, CoffeeScript is just of bunch of folks who enjoy working on the compiler and helping others. You certainly shouldn't expect the same level of secondary effort as in Dart or TypeScript - yet I think CoffeeScript is doing great on this front.

[roryokane]

I described some details that would help implement a rich code editor (like CodeMirror) in Try CoffeeScript in this issue:

“Use rich code editor in Try CoffeeScript on coffeescript.org” – https://github.com/jashkenas/coffee-script/issues/3076

I’m glad to hear that compile errors will finally be displayed in the output area in the next release (https://github.com/jashkenas/coffee-script/pull/3425). If anyone feels like improving that interface even further, they could try implementing the mockup in this issue:

“Highlight code errors and move error message in Try CoffeeScript” – https://github.com/jashkenas/coffee-script/issues/3077

[mraleph]

> But both are better than the Dart sandbox, which basically only says "error"

Compilation errors are attributed to the place where they occurred and highlighted there with a red underline. Actual error is displayed on hover.