Can be used as both an npm module and also on the browser.
npm install validifyjs
Add html attribute "data-validify" to the element to be validated. The value of the attribute would decide what validation is to be done.
Individual methods and validateForm(formElements) can be called for validation, as mentioned in the case for the browser.
In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.