Functional Javascript

Functional is a library for functional programming in JavaScript. It defines the standard higher-order functions such as map, reduce (aka foldl), and select (aka filter). It also defines functions such as curry, rcurry, and partial for partial function application; and compose, guard, and until for function-level programming. And all these functions accept strings, such as 'x -> x+1', 'x+1', or '+1' as synonyms for the more verbose function(x) {return x+1}.

Ports: String#to_proc (Ruby; Reginald Braithwaite), Erlang (Debasish Ghosh), Dojo (Eugene Lazutkin).
Related: Sequentially, Fluently, MVars.

Functional supports higher-order programming:

          map('x*x', [1,2,3,4])
            → [1, 4, 9, 16]
          select('>2', [1,2,3,4])
            → [3, 4]
          reduce('x*2+y', 0, [1,0,1,0])
            → 10
          map(guard('2*', not('%2')), [1,2,3,4])
            → [1, 4, 3, 8]
        

…as well as function-level (or pointless) style:

          until('>100', 'x*x')(2)
            → 256
          var squareUntil = until.partial(_, 'x*x');
          var square2Until = squareUntil.uncurry().flip().curry(2);
          var firstSquare2Over = compose(square2Until, 'n -> i -> i > n');
          firstSquare2Over(100)
            → 256
        

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