transform all ObjectId inside an object to a string to make it easy test assertions

mongooseObjectIdToString.ts

import mongoose from 'mongoose';

const { ObjectId } = mongoose.Types;

// transform all ObjectId to string
export const mongooseObjectIdToString = (data: any) => {
  if (!data) {
    return data;
  }

  if (Array.isArray(data)) {
    return data.map(d => mongooseObjectIdToString(d));
  }

  if (
    ObjectId.isValid(data) &&
    data.toString().indexOf(data) !== -1
  ) {
    return data.toString();
  }

  if (typeof data === 'object' && !Array.isArray(data)) {
    return Object.keys(data).reduce((prev, curr) => ({
        ...prev,
        [curr]: mongooseObjectIdToString(data[curr]),
      }), {});
  }

  return data;
};