Echo JS 0.11.0

functional programming uses programmatic functions in the same way that mathematicians use functions[0].  This has some important implications, including the facts that there won't be any side-effects and that the same inputs will always result in the same outputs.  These are among the reasons that functional programming and the concept of immutable data [1] are so correlated.  

[0] https://en.wikipedia.org/wiki/Function_(mathematics)  

[1] https://en.wikipedia.org/wiki/Immutable