check_mongodb_objectid_str_pattern.js

/* 
useful references

regex pattern
https://github.com/mongodb/js-bson/blob/v4.2.0/src/objectid.ts#L9

validation function
https://github.com/mongodb/js-bson/blob/v4.2.0/src/objectid.ts#L301

/^([a-zA-Z0-9]{24}|[a-zA-Z0-9]{12})$/
https://jex.im/regulex/#!flags=&re=%5E(%5Ba-zA-Z0-9%5D%7B24%7D%7C%5Ba-zA-Z0-9%5D%7B12%7D)%24
*/

function isValidObjectID(str) {
  // coerce to string so the function can be generically used to test both strings and native objectIds created by the driver
  str = str + '';
  var len = str.length, valid = false;
  if (len == 12 || len == 24) {
    valid = /^[a-zA-Z0-9]+$/.test(str);
  }
  return valid;
}