Source: node_modules/mongodb-client-encryption/lib/common.js

'use strict';
/**
 * @ignore
 * Helper function for logging. Enabled by setting the environment flag MONGODB_CRYPT_DEBUG.
 * @param {*} msg Anything you want to be logged.
 */
function debug(msg) {
  if (process.env.MONGODB_CRYPT_DEBUG) {
    console.log(msg);
  }
}
/**
 * @ignore
 * Gets the database portion of a namespace string
 * @param {string} ns A string in the format of a namespace (database.collection)
 * @returns {string} The database portion of the namespace
 */
function databaseNamespace(ns) {
  return ns.split('.')[0];
}
/**
 * @ignore
 * Gets the colleciton portion of a namespace string
 * @param {string} ns A string in the format of a namespace (database.collection)
 * @returns {string} The collection portion of the namespace
 */
function collectionNamespace(ns) {
  return ns
    .split('.')
    .slice(1)
    .join('.');
}
/**
 * @class
 * An error indicating that something went wrong specifically with MongoDB Client Encryption
 */
class MongoCryptError extends Error {
  constructor(message) {
    super(message);
    this.name = 'MongoCryptError';
    Error.captureStackTrace(this, this.constructor);
  }
}
/**
 * @ignore
 * A helper function. Invokes a function that takes a callback as the final
 * parameter. If a callback is supplied, then it is passed to the function.
 * If not, a Promise is returned that resolves/rejects with the result of the
 * callback
 * @param {Function} [callback] an optional callback.
 * @param {Function} fn A function that takes a callback
 * @returns {Promise|void} Returns nothing if a callback is supplied, else returns a Promise.
 */
function promiseOrCallback(callback, fn) {
  if (typeof callback === 'function') {
    fn(function(err) {
      if (err != null) {
        try {
          callback(err);
        } catch (error) {
          return process.nextTick(() => {
            throw error;
          });
        }
        return;
      }
      callback.apply(this, arguments);
    });
    return;
  }
  return new Promise((resolve, reject) => {
    fn(function(err, res) {
      if (err != null) {
        return reject(err);
      }
      if (arguments.length > 2) {
        return resolve(Array.prototype.slice.call(arguments, 1));
      }
      resolve(res);
    });
  });
}
module.exports = {
  debug,
  databaseNamespace,
  collectionNamespace,
  MongoCryptError,
  promiseOrCallback
};