JavaScript@javascript · channel · 30 984 subscribers✅ High trust

Post CHALLENGE

17 September 2026

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JavaScript

CHALLENGE const nums = [1, 2, 3, 4, 5]; const result = nums .filter(n => n % 2 !== 0) .map(n => n ** 2) .reduce((acc, n) => acc + n, 0); const arr = [10, , 20, undefined, 30]; const mapped = arr.map(x => x * 2); console.log(result, mapped);

1 · 2.1K · 06:31

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JavaScript06:30CHALLENGE let count = 0; const inc = () => (count += 1, count); const a = 0 || inc(); const b = null ?? inc(); const c = a && inc(); const d = b?.toString() || J

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JavaScript06:31Poll J

JavaScript06:31CHALLENGE let i = 0; const key = () => `k${i++}`; const obj = { [key()]: i, [key()]: i, [key()]: i, }; console.log(Object.keys(obj).join(','), obj.k0, obj.k1, o

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JavaScript

JavaScript@javascript · channel · Tech

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