Is chaining map, filter, and reduce inefficient for large arrays in JavaScript?
Each chain step creates a new array (multiple passes). For large arrays and many steps, a single reduce or a single loop may be faster. But chaining is more readable; only optimize if profiling shows a problem.
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More FAQs in Common Higher-Order Function Mistakes in JavaScript
Because map returns a new array, which is wasted if you only want side effects. forEach returns undefined and signals that you are not transforming data. Using map for side effects is misleading and wastes memory.
Because without an initial value, reduce uses the first element as the accumulator. An empty array has no first element, so it throws TypeError: Reduce of empty array with no initial value. Always pass an initial value.
Because sort defaults to string comparison. It converts elements to strings and sorts lexicographically. '10' comes before '2' because '1' < '2'. Use a numeric comparator: sort((a, b) => a - b).
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