node_modules/generic-pool/lib/factoryValidator.js

module.exports = function(factory) {
  if (typeof factory.create !== "function") {
    throw new TypeError("factory.create must be a function");
  }

  if (typeof factory.destroy !== "function") {
    throw new TypeError("factory.destroy must be a function");
  }

  if (
    typeof factory.validate !== "undefined" &&
    typeof factory.validate !== "function"
  ) {
    throw new TypeError("factory.validate must be a function");
  }
};