Remove array elements from the end until condition is met

JavaScript, Array · Nov 29, 2020

Removes elements from the end of an array until the passed function returns true. Returns the removed elements.

const takeRightUntil = (arr, fn) => {
  for (const [i, val] of [...arr].reverse().entries())
    if (fn(val)) return i === 0 ? [] : arr.slice(-i);
  return arr;
};
takeRightUntil([1, 2, 3, 4], n => n < 3); // [3, 4]

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