JavaScript deep clone function

cloneDeep.js

function cloneDeep(objSource) {
  if (objSource instanceof Date) {
      return new Date(objSource);
  }

  const plainObject = {};

  if (!(objSource instanceof Object) || objSource instanceof String) {
      return objSource;
  }

  const objClone = Array.isArray(objSource) ? [] : plainObject;
  Object.entries(objSource).forEach(([key, value]) => {
    let vValue = value;

    if (typeof value === typeof plainObject) {
        vValue = cloneDeep(value);
    }

    objClone[key] = vValue;
  });

  return objClone;
}