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Starter#Arrays#Polyfill
Array.prototype.filter Polyfill
Implement Array.prototype.filter from scratch. The key detail: push the original element, not the boolean result of the predicate.
By modernDev2026-06-05Easy
filter is deceptively simple — keep elements where the callback returns truthy. The trap most candidates fall into is pushing the boolean return value instead of the original element. Get the callback signature right, support thisArg, and you have a correct implementation.
Goal: Implement myFilter correctly. Focus on pushing the original element, not the predicate result.
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