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Custom filter — higher-order function

📖 Usage Example
function myFilter(arr, predicate) {
  const result = [];
  for (const item of arr) if (predicate(item)) result.push(item);
  return result;
}
myFilter([1, 2, 3, 4], x => x % 2 === 0); // [2, 4]

A custom filter passes only items for which the predicate returns true.

Filtering with Higher-Order Functions

Create a custom filter function that keeps only elements matching a predicate.

Challenge: Implement myFilter that takes an array and a predicate function, returning only elements where the predicate is true.

💡 Hints (3)
  • • Use reduce with conditional logic
  • • Include x if predicate(x) is true
  • • Otherwise keep accumulator unchanged