Opa vs Babel (6to5)
When comparing Opa vs Babel (6to5), the Slant community recommends Babel (6to5) for most people. In the question“What are the best languages that compile to JavaScript? ” Babel (6to5) is ranked 8th while Opa is ranked 30th. The most important reason people chose Babel (6to5) is:
Babel will turn your ES6+ code into ES5 friendly code, so you can start using it right now without waiting for browser support.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Type Inferred
Opa uses type inference to decide what code runs on the client or the server, so you can organize code how you like, but still be sure that it runs where it needs to.
Pro Familiar Javascript Syntax
Opa's syntax is very similar to JavaScript, making it an easy choice for developers who are used to developing in JavaScript.
Pro Client and Server in the same language
Pro Support ES6(Harmony)
Babel will turn your ES6+ code into ES5 friendly code, so you can start using it right now without waiting for browser support.
Pro Plugins for custom features
Pro Future forward thinking
Cons
Con Not popular
Opa is not as popular as other languages which compile to JavaScript. Making it harder to find learning resources or even answers if you get stuck somewhere.
Con Generated ES5 is ugly and performs badly
Output looks far from handwritten ES5, is quite large with a lot of extra statements to execute.