# <auto-check> element An input element that validates its value against a server endpoint. ## Installation ``` $ npm install --save auto-check-element ``` ## Usage ```js import 'auto-check-element' ``` ```erb "> ``` Provide a URL and a CSRF token and the autocheck component will show validation confirmations and validation errors. The endpoint should respond to POST requests with: - a 200 HTTP status code if the provided value if valid. - a 422 HTTP status code if the provided value is invalid. - a optional error message in the body and a `Content-Type` header with a value of `text/html; fragment`. ## Events ```js const check = document.querySelector('auto-check') // Network request lifecycle events. check.addEventListener('loadstart', function(event) { console.log('Network request started', event) }) check.addEventListener('loadend', function(event) { console.log('Network request complete', event) }) check.addEventListener('load', function(event) { console.log('Network request succeeded', event) }) check.addEventListener('error', function(event) { console.log('Network request failed', event) }) // Auto-check result events. const input = check.querySelector('input') input.addEventListener('auto-check-send', function(event) { console.log('Adding to FormData before network request is sent.') const {body} = event.detail body.append('custom_form_data', 'value') }) input.addEventListener('auto-check-success', function(event) { const {message} = event.detail console.log('Validation passed', message) }) input.addEventListener('auto-check-error', function(event) { const {message} = event.detail console.log('Validation failed', message) }) input.addEventListener('auto-check-complete', function(event) { console.log('Validation complete', event) }) ``` ## Browser support Browsers without native [custom element support][support] require a [polyfill][]. - Chrome - Firefox - Safari - Microsoft Edge [support]: https://caniuse.com/#feat=custom-elementsv1 [polyfill]: https://github.com/webcomponents/custom-elements ## Development ``` npm install npm test ``` ## License Distributed under the MIT license. See LICENSE for details.