Functional JavaScript
Written by on July 24th, 2007 in Ajax News.
Oliver Steele has a new library called Functional JavaScript that defines the standard higher-order functions (map, reduce, filter) as well as functions for partial function application and function-level programming: curry, partial, compose, guard, and until. Finally, it introduces “string lambdas”, which let you write ‘x -> x+1′, ‘x+1′, or even ‘+1′ as synonyms for function(x) {return x+1}.
His documentation / API page also has a living interpreter within, so you can test how functional you are.
If this looks fun to you, check it out:
JAVASCRIPT:
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map(’x*x’, [1,2,3,4])
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// → [1, 4, 9, 16]
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select(’>2′, [1,2,3,4])
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// → [3, 4]
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reduce(’x*2+y’, 0, [1,0,1,0])
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// → 10
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map(guard(’2*’, not(’%2′)), [1,2,3,4])
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// → [1, 4, 3, 8]
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until(’>100′, ‘x*x’)(2)
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// → 256
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var squareUntil = until.partial(_, ‘x*x’);
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var square2Until = squareUntil.uncurry().flip().curry(2);
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var firstSquare2Over = compose(square2Until, ‘n -> i -> i> n’);
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firstSquare2Over(100)
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// → 256
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Source: Ajaxian
Original Article: http://feeds.feedburner.com/~r/ajaxian/~3/136919349/functional-javascript