Higher-Order Functions and Composition: map/filter/reduce, Currying and Building Pipelines
A higher-order function takes or returns functions; composition connects them into a new function, and its order is a business rule. We combine Bookstore's coupon and member discount as Func<decimal, decimal> rules with Then, Compose and Pipe, test that the order changes the result by 1.50 TL, and show fold, currying, a TypeScript pipe and the cost of closure allocations with real output.
15 Nov 2026
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12 min
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10
