How to use

findLastIndex

function

in

lodash

const sliceHunk = ({changes}, startOldLineNumber, endOldLineNumber) => {
  const changeIndex = changes.findIndex(change => computeOldLineNumber(change) >= startOldLineNumber);

  if (changeIndex === -1) {
    return null;
  }

  // It is possible to have some insert changes before `startOldLineNumber`,
  // since we slice from old line number, these changes can be ommited, so we need to grab them back
  const startIndex = (() => {
    if (changeIndex === 0) {
      return changeIndex;
    }

    const nearestHeadingNocmalChangeIndex = findLastIndex(changes, change => !change.isInsert, changeIndex - 1);
    return nearestHeadingNocmalChangeIndex === -1 ? changeIndex : nearestHeadingNocmalChangeIndex + 1;
  })();

  if (endOldLineNumber === undefined) {
    const slicedChanges = changes.slice(startIndex);

    return createHunkFromChanges(slicedChanges);
  }

  const endIndex = findLastIndex(changes, change => computeOldLineNumber(change) <= endOldLineNumber);
  const slicedChanges = changes.slice(startIndex, endIndex === -1 ? undefined : endIndex);

  return createHunkFromChanges(slicedChanges);
}