src/utils/objectId.js

const { Types } = require('mongoose');

function toValidObjectIdStrings(values = []) {
  const ids = new Set();

  for (const value of values) {
    if (value === null || value === undefined) continue;
    const normalized = String(value).trim();
    if (!normalized) continue;
    if (Types.ObjectId.isValid(normalized)) {
      ids.add(normalized);
    }
  }

  return [...ids];
}

module.exports = {
  toValidObjectIdStrings
};