React App

├── README.md ├── package.json ├── public ├── favicon.ico ├── index.html └── manifest.json └── src ├── App.js ├── Form.js ├── LoginFormValidationRules.js ├── index.css ├── index.js ├── serviceWorker.js └── useForm.js /README.md: -------------------------------------------------------------------------------- 1 | 2 | ## Form Validation using Custom React Hooks 3 | 4 | The full tutorial for building this project can be found over at Upmostly.com: [Form Validation Using Custom React Hooks](https://upmostly.com/tutorials/form-validation-using-custom-react-hooks). 5 | 6 | ![A login form built in React and using custom React Hooks to power the form validation](https://upmostly.com/wp-content/uploads/react-hooks-form-validation.gif) 7 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "form-validation-react-hooks", 3 | "version": "0.1.0", 4 | "private": true, 5 | "dependencies": { 6 | "bulma": "^0.7.4", 7 | "react": "^16.8.2", 8 | "react-dom": "^16.8.2", 9 | "react-scripts": "2.1.5" 10 | }, 11 | "scripts": { 12 | "start": "react-scripts start", 13 | "build": "react-scripts build", 14 | "test": "react-scripts test", 15 | "eject": "react-scripts eject" 16 | }, 17 | "eslintConfig": { 18 | "extends": "react-app" 19 | }, 20 | "browserslist": [ 21 | ">0.2%", 22 | "not dead", 23 | "not ie <= 11", 24 | "not op_mini all" 25 | ] 26 | } 27 | -------------------------------------------------------------------------------- /public/favicon.ico: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/upmostly/custom-react-hooks-form-validation/7d08e8b7d65f1387d42ae1632493b756f972f81c/public/favicon.ico -------------------------------------------------------------------------------- /public/index.html: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | 10 | 11 | 15 | 16 | 25 | React App 26 | 27 | 28 | 29 |

30 | 40 | 41 | 42 | -------------------------------------------------------------------------------- /public/manifest.json: -------------------------------------------------------------------------------- 1 | { 2 | "short_name": "React App", 3 | "name": "Create React App Sample", 4 | "icons": [ 5 | { 6 | "src": "favicon.ico", 7 | "sizes": "64x64 32x32 24x24 16x16", 8 | "type": "image/x-icon" 9 | } 10 | ], 11 | "start_url": ".", 12 | "display": "standalone", 13 | "theme_color": "#000000", 14 | "background_color": "#ffffff" 15 | } 16 | -------------------------------------------------------------------------------- /src/App.js: -------------------------------------------------------------------------------- 1 | import React from 'react'; 2 | import Form from './Form'; 3 | 4 | const App = () => { 5 | return ( 6 |

7 | ); 8 | }; 9 | 10 | export default App; 11 | -------------------------------------------------------------------------------- /src/Form.js: -------------------------------------------------------------------------------- 1 | import React from 'react'; 2 | import useForm from "./useForm"; 3 | import validate from './LoginFormValidationRules'; 4 | 5 | const Form = () => { 6 | const { 7 | values, 8 | errors, 9 | handleChange, 10 | handleSubmit, 11 | } = useForm(login, validate); 12 | 13 | function login() { 14 | console.log('No errors, submit callback called!'); 15 | } 16 | 17 | return ( 18 |

19 |

20 |

21 |

22 | 23 |

24 | Email Address 25 |

26 | 27 | {errors.email && ( 28 |

{errors.email}

29 | )} 30 |

31 |

32 |

33 | Password 34 |

35 | 36 |

37 | {errors.password && ( 38 |

{errors.password}

39 | )} 40 |

41 | 42 | 43 |

44 |

45 |

46 |

47 | ); 48 | }; 49 | 50 | export default Form; 51 | -------------------------------------------------------------------------------- /src/LoginFormValidationRules.js: -------------------------------------------------------------------------------- 1 | export default function validate(values) { 2 | let errors = {}; 3 | if (!values.email) { 4 | errors.email = 'Email address is required'; 5 | } else if (!/\S+@\S+\.\S+/.test(values.email)) { 6 | errors.email = 'Email address is invalid'; 7 | } 8 | if (!values.password) { 9 | errors.password = 'Password is required'; 10 | } else if (values.password.length < 8) { 11 | errors.password = 'Password must be 8 or more characters'; 12 | } 13 | return errors; 14 | }; 15 | -------------------------------------------------------------------------------- /src/index.css: -------------------------------------------------------------------------------- 1 | body { 2 | margin: 0; 3 | padding: 0; 4 | font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", 5 | "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", 6 | sans-serif; 7 | -webkit-font-smoothing: antialiased; 8 | -moz-osx-font-smoothing: grayscale; 9 | } 10 | 11 | code { 12 | font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New", 13 | monospace; 14 | } 15 | -------------------------------------------------------------------------------- /src/index.js: -------------------------------------------------------------------------------- 1 | import React from 'react'; 2 | import ReactDOM from 'react-dom'; 3 | import './index.css'; 4 | import App from './App'; 5 | import * as serviceWorker from './serviceWorker'; 6 | import 'bulma/css/bulma.css'; 7 | 8 | ReactDOM.render(, document.getElementById('root')); 9 | 10 | // If you want your app to work offline and load faster, you can change 11 | // unregister() to register() below. Note this comes with some pitfalls. 12 | // Learn more about service workers: http://bit.ly/CRA-PWA 13 | serviceWorker.unregister(); 14 | -------------------------------------------------------------------------------- /src/serviceWorker.js: -------------------------------------------------------------------------------- 1 | // This optional code is used to register a service worker. 2 | // register() is not called by default. 3 | 4 | // This lets the app load faster on subsequent visits in production, and gives 5 | // it offline capabilities. However, it also means that developers (and users) 6 | // will only see deployed updates on subsequent visits to a page, after all the 7 | // existing tabs open on the page have been closed, since previously cached 8 | // resources are updated in the background. 9 | 10 | // To learn more about the benefits of this model and instructions on how to 11 | // opt-in, read http://bit.ly/CRA-PWA 12 | 13 | const isLocalhost = Boolean( 14 | window.location.hostname === 'localhost' || 15 | // [::1] is the IPv6 localhost address. 16 | window.location.hostname === '[::1]' || 17 | // 127.0.0.1/8 is considered localhost for IPv4. 18 | window.location.hostname.match( 19 | /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/ 20 | ) 21 | ); 22 | 23 | export function register(config) { 24 | if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) { 25 | // The URL constructor is available in all browsers that support SW. 26 | const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href); 27 | if (publicUrl.origin !== window.location.origin) { 28 | // Our service worker won't work if PUBLIC_URL is on a different origin 29 | // from what our page is served on. This might happen if a CDN is used to 30 | // serve assets; see https://github.com/facebook/create-react-app/issues/2374 31 | return; 32 | } 33 | 34 | window.addEventListener('load', () => { 35 | const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`; 36 | 37 | if (isLocalhost) { 38 | // This is running on localhost. Let's check if a service worker still exists or not. 39 | checkValidServiceWorker(swUrl, config); 40 | 41 | // Add some additional logging to localhost, pointing developers to the 42 | // service worker/PWA documentation. 43 | navigator.serviceWorker.ready.then(() => { 44 | console.log( 45 | 'This web app is being served cache-first by a service ' + 46 | 'worker. To learn more, visit http://bit.ly/CRA-PWA' 47 | ); 48 | }); 49 | } else { 50 | // Is not localhost. Just register service worker 51 | registerValidSW(swUrl, config); 52 | } 53 | }); 54 | } 55 | } 56 | 57 | function registerValidSW(swUrl, config) { 58 | navigator.serviceWorker 59 | .register(swUrl) 60 | .then(registration => { 61 | registration.onupdatefound = () => { 62 | const installingWorker = registration.installing; 63 | if (installingWorker == null) { 64 | return; 65 | } 66 | installingWorker.onstatechange = () => { 67 | if (installingWorker.state === 'installed') { 68 | if (navigator.serviceWorker.controller) { 69 | // At this point, the updated precached content has been fetched, 70 | // but the previous service worker will still serve the older 71 | // content until all client tabs are closed. 72 | console.log( 73 | 'New content is available and will be used when all ' + 74 | 'tabs for this page are closed. See http://bit.ly/CRA-PWA.' 75 | ); 76 | 77 | // Execute callback 78 | if (config && config.onUpdate) { 79 | config.onUpdate(registration); 80 | } 81 | } else { 82 | // At this point, everything has been precached. 83 | // It's the perfect time to display a 84 | // "Content is cached for offline use." message. 85 | console.log('Content is cached for offline use.'); 86 | 87 | // Execute callback 88 | if (config && config.onSuccess) { 89 | config.onSuccess(registration); 90 | } 91 | } 92 | } 93 | }; 94 | }; 95 | }) 96 | .catch(error => { 97 | console.error('Error during service worker registration:', error); 98 | }); 99 | } 100 | 101 | function checkValidServiceWorker(swUrl, config) { 102 | // Check if the service worker can be found. If it can't reload the page. 103 | fetch(swUrl) 104 | .then(response => { 105 | // Ensure service worker exists, and that we really are getting a JS file. 106 | const contentType = response.headers.get('content-type'); 107 | if ( 108 | response.status === 404 || 109 | (contentType != null && contentType.indexOf('javascript') === -1) 110 | ) { 111 | // No service worker found. Probably a different app. Reload the page. 112 | navigator.serviceWorker.ready.then(registration => { 113 | registration.unregister().then(() => { 114 | window.location.reload(); 115 | }); 116 | }); 117 | } else { 118 | // Service worker found. Proceed as normal. 119 | registerValidSW(swUrl, config); 120 | } 121 | }) 122 | .catch(() => { 123 | console.log( 124 | 'No internet connection found. App is running in offline mode.' 125 | ); 126 | }); 127 | } 128 | 129 | export function unregister() { 130 | if ('serviceWorker' in navigator) { 131 | navigator.serviceWorker.ready.then(registration => { 132 | registration.unregister(); 133 | }); 134 | } 135 | } 136 | -------------------------------------------------------------------------------- /src/useForm.js: -------------------------------------------------------------------------------- 1 | import { useState, useEffect } from 'react'; 2 | 3 | const useForm = (callback, validate) => { 4 | 5 | const [values, setValues] = useState({}); 6 | const [errors, setErrors] = useState({}); 7 | const [isSubmitting, setIsSubmitting] = useState(false); 8 | 9 | useEffect(() => { 10 | if (Object.keys(errors).length === 0 && isSubmitting) { 11 | callback(); 12 | } 13 | }, [errors]); 14 | 15 | const handleSubmit = (event) => { 16 | if (event) event.preventDefault(); 17 | setErrors(validate(values)); 18 | setIsSubmitting(true); 19 | }; 20 | 21 | const handleChange = (event) => { 22 | event.persist(); 23 | setValues(values => ({ ...values, [event.target.name]: event.target.value })); 24 | }; 25 | 26 | return { 27 | handleChange, 28 | handleSubmit, 29 | values, 30 | errors, 31 | } 32 | }; 33 | 34 | export default useForm; --------------------------------------------------------------------------------