Haste vs GHCJS

Haste was designed to allow both the client and server to be written as parts of the same, type-safe application. This is in stark contrast to most other options, where the client and server are considered two separate entities, resulting in extra manual validation code and more chances for type errors.

Haste supports the Haskell 2010 standard except for Template Haskell as well as most GHC extensions.

Haste lets you write client and server as a single program, automatically generating code for the server as well as the client, giving you full type safety even across the Internet.

With a Haskell backend, GHCJS enables code sharing. In combination with the power of Haskell as a language, this enables an extremely tight integration of the client side with the server side, where all the communications take place in a type-safe manner and even transparently if desired.

No need to learn new syntax or semantics, and no need to install and learn a bunch of new tools - it's just GHC.

Haskell is a very terse language, particularly due to its type inference. This means there's nothing to distract from the intent of the code, making it very readable. This is in sharp contrast to languages like Java, where skimming code requires learning which details can be ignored. Haskell's terseness also lends itself to very clear inline examples in textbooks, and makes it a pleasure to read through code even on a cellphone screen.

It's often said that, in Haskell, if it compiles, it works. This short feedback loop can speed up learning process, by making it clear exactly when and where mistakes are made.