According to Sébastien Doeraene, member of the Scala team, many users believe that Scala.js is already production-ready, but this release brings more stability to the compiler. In version 6.0, the semantics of the language have been established and the standard library will continue to be backward and binary compatible, according to Doeraene.
“Of course, we must still be able to evolve the library and the builds, so things might become deprecated, and eventually removed, but will do so at a slower pace than before,” Doeraene wrote on the Scala blog. “All things considered, this means that the code you write today for Scala.js 0.6.0 will continue to work throughout 0.6.x and 1.x.y unchanged.”
The Scala team is releasing Scala.js into production before its 1.0 release because it wants to give itself some time to modify the compiler’s intermediate format before heading to version 1.0, according to Doeraene.
“Though, rest assured we’re confident that Scala.js is otherwise stable and ready for widespread adoption,” he wrote.
More information is available here.