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Take While and Drop While Array Helpers

Implement takeWhile and dropWhile helpers that stop testing after the first failure and never mutate the source array.

JavascriptData Integrity

Code

snippet
export function takeWhile(items, predicate) {
  if (!Array.isArray(items)) throw new TypeError("items must be an array");
  if (typeof predicate !== "function") throw new TypeError("predicate must be a function");
  const result = [];
  for (const item of items) {
    if (!predicate(item)) break;
    result.push(item);
  }
  return result;
}

export function dropWhile(items, predicate) {
  if (!Array.isArray(items)) throw new TypeError("items must be an array");
  if (typeof predicate !== "function") throw new TypeError("predicate must be a function");
  let index = 0;
  while (index < items.length && predicate(items[index])) index += 1;
  return items.slice(index);
}

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