Just want to second this. As someone who did not know Haskell going in, I found PureScript to be quite useful because I could look at the generated Javascript to understand exactly what it's doing under the hood. I've since been able to use what I learned in PureScript in Haskell with very little difficulty.
If you are originally setting out to generate Javascript, I think PureScript is even more compelling. The code it outputs is really gorgeous. It is also optimised for that environment. Specifically some features in Haskell that would be difficult to implement in Javascript are not present. Also, the very few places where the syntax differs tends to make the code generation very predictable.
I haven't used it in a big project yet, but from playing around with it, I wouldn't hesitate to do so.
If you are originally setting out to generate Javascript, I think PureScript is even more compelling. The code it outputs is really gorgeous. It is also optimised for that environment. Specifically some features in Haskell that would be difficult to implement in Javascript are not present. Also, the very few places where the syntax differs tends to make the code generation very predictable.
I haven't used it in a big project yet, but from playing around with it, I wouldn't hesitate to do so.