Travelopia · junaidbhura · Nov 19, 2023 · Nov 17, 2023 · Nov 17, 2023 · Nov 17, 2023
diff --git a/src/form/definitions.d.ts b/src/form/definitions.d.ts
@@ -0,0 +1,26 @@
+/**
+ * Internal dependencies.
+ */
+import { TPFormFieldElement } from './tp-form-field';
+
+/**
+ * Form Validator.
+ */
+export interface TPFormValidator {
+	validate: { ( field: TPFormFieldElement ): boolean };
+	getErrorMessage: { ( field: TPFormFieldElement ): string };
+}
+
+/**
+ * Window.
+ */
+declare global {
+	interface Window {
+		tpFormValidators: {
+			[ key: string ]: TPFormValidator;
+		}
+		tpFormErrors: {
+			[ key: string ]: string;
+		};
+	}
+}
diff --git a/src/form/index.html b/src/form/index.html
@@ -0,0 +1,65 @@
+<!doctype html>
+<html lang="en">
+<head>
+	<meta charset="UTF-8">
+	<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
+	<meta http-equiv="X-UA-Compatible" content="ie=edge">
+	<title>Web Component: Form</title>
+
+	<link rel="stylesheet" href="../../dist/form/style.css" media="all">
+	<script type="module" src="../../dist/form/index.js"></script>
+
+	<style>
+		form {
+			display: flex;
+			flex-direction: column;
+			gap: 10px;
+			max-width: 600px;
+			margin: 40px auto;
+		}
+
+		tp-form-field,
+		label {
+			display: block;
+		}
+
+		input,
+		select,
+		textarea {
+			width: 100%;
+		}
+	</style>
+</head>
+<body>
+	<main>
+		<tp-form prevent-submit="yes">
+			<form action="#">
+				<tp-form-field required="yes">
+					<label>Field 1</label>
+					<input type="text" name="field_1">
+				</tp-form-field>
+				<tp-form-field required="yes" email="yes">
+					<label>Field 2</label>
+					<input type="email" name="field_2">
+				</tp-form-field>
+				<tp-form-field required="yes">
+					<label>Field 3</label>
+					<select type="text" name="field_3">
+						<option value="">Select value</option>
+						<option value="value_1">Value 1</option>
+						<option value="value_2">Value 2</option>
+						<option value="value_3">Value 3</option>
+					</select>
+				</tp-form-field>
+				<tp-form-field min-length="4" max-length="8">
+					<label>Field 4</label>
+					<textarea name="field_4"></textarea>
+				</tp-form-field>
+				<tp-form-submit submitting-text="Submitting...">
+					<button type="submit">Submit</button>
+				</tp-form-submit>
+			</form>
+		</tp-form>
+	</main>
+</body>
+</html>
diff --git a/src/form/index.ts b/src/form/index.ts
@@ -0,0 +1,50 @@
+/**
+ * Styles.
+ */
+import './style.scss';
+
+/**
+ * Validators.
+ */
+import { TPFormValidator } from './definitions';
+import * as required from './validators/required';
+import * as email from './validators/email';
+import * as minLength from './validators/min-length';
+import * as maxLength from './validators/max-length';
+
+const validators = [
+	required,
+	email,
+	minLength,
+	maxLength,
+];
+
+/**
+ * Register Validators and Errors.
+ */
+window.tpFormValidators = {};
+window.tpFormErrors = {};
+
+validators.forEach( (
+	{ name, validator, errorMessage }: { name: string, validator: TPFormValidator, errorMessage: string }
+): void => {
+	window.tpFormValidators[ name ] = validator;
+	window.tpFormErrors[ name ] = errorMessage;
+} );
+
+/**
+ * Components.
+ */
+import { TPFormElement } from './tp-form';
+import { TPFormFieldElement } from './tp-form-field';
+import { TPFormErrorElement } from './tp-form-error';
+import { TPFormSubmitElement } from './tp-form-submit';
+
+/**
+ * Register Components.
+ */
+customElements.define( 'tp-form', TPFormElement );
+customElements.define( 'tp-form-field', TPFormFieldElement );
+customElements.define( 'tp-form-error', TPFormErrorElement );
+customElements.define( 'tp-form-submit', TPFormSubmitElement );
+
diff --git a/src/form/style.scss b/src/form/style.scss
diff --git a/src/form/tp-form-error.ts b/src/form/tp-form-error.ts
@@ -0,0 +1,5 @@
+/**
+ * TP Form Error.
+ */
+export class TPFormErrorElement extends HTMLElement {
+}
diff --git a/src/form/tp-form-field.ts b/src/form/tp-form-field.ts
@@ -0,0 +1,150 @@
+/**
+ * Internal dependencies.
+ */
+import { TPFormErrorElement } from './tp-form-error';
+
+/**
+ * TP Form Field.
+ */
+export class TPFormFieldElement extends HTMLElement {
+	/**
+	 * Connected callback.
+	 */
+	connectedCallback(): void {
+		const field = this.getField();
+		field?.addEventListener( 'keyup', this.handleFieldChanged.bind( this ) );
+		field?.addEventListener( 'change', this.handleFieldChanged.bind( this ) );
+	}
+
+	/**
+	 * Update validation when the field has changed.
+	 */
+	handleFieldChanged(): void {
+		if ( this.getAttribute( 'valid' ) || this.getAttribute( 'error' ) ) {
+			this.validate();
+		}
+	}
+
+	/**
+	 * Get observed attributes.
+	 *
+	 * @return {Array} List of observed attributes.
+	 */
+	static get observedAttributes(): string[] {
+		return [ 'valid', 'error' ];
+	}
+
+	/**
+	 * Attribute changed callback.
+	 *
+	 * @param {string} name     Attribute name.
+	 * @param {string} oldValue Old value.
+	 * @param {string} newValue New value.
+	 */
+	attributeChangedCallback( name: string = '', oldValue: string = '', newValue: string = '' ): void {
+		if ( ( 'valid' === name || 'error' === name ) && oldValue !== newValue ) {
+			this.dispatchEvent( new CustomEvent( 'validate', { bubbles: true } ) );
+		}
+		this.update();
+	}
+
+	/**
+	 * Update component.
+	 */
+	update(): void {
+		const { tpFormValidators } = window;
+		if ( ! tpFormValidators ) {
+			return;
+		}
+
+		const error: string = this.getAttribute( 'error' ) ?? '';
+		if ( '' !== error && error in tpFormValidators && 'function' === typeof tpFormValidators[ error ].getErrorMessage ) {
+			this.setErrorMessage( tpFormValidators[ error ].getErrorMessage( this ) );
+		} else {
+			this.removeErrorMessage();
+		}
+	}
+
+	/**
+	 * Get the associated field.
+	 *
+	 * @return {HTMLElement} The associated field for this component.
+	 */
+	getField(): HTMLInputElement | HTMLSelectElement | HTMLTextAreaElement | null {
+		return this.querySelector( 'input,select,textarea' );
+	}
+
+	/**
+	 * Validate this field.
+	 *
+	 * @return {boolean} Whether this field passed validation.
+	 */
+	validate(): boolean {
+		// Look for validators.
+		const { tpFormValidators } = window;
+		if ( ! tpFormValidators ) {
+			return true;
+		}
+
+		// Prepare error and valid status.
+		let valid: boolean = true;
+		let error: string = '';
+		const allAttributes: string[] = this.getAttributeNames();
+
+		// Traverse all attributes to see if we find a matching validator.
+		allAttributes.every( ( attributeName: string ): boolean => {
+			if ( attributeName in tpFormValidators && 'function' === typeof tpFormValidators[ attributeName ].validate ) {
+				// We found one, lets validate the field.
+				const isValid: boolean = tpFormValidators[ attributeName ].validate( this );
+
+				// Looks like we found an error!
+				if ( false === isValid ) {
+					valid = false;
+					error = attributeName;
+					return false;
+				}
+			}
+
+			// No error found, all good.
+			return true;
+		} );
+
+		// Check if the field is valid or not.
+		if ( valid ) {
+			this.setAttribute( 'valid', 'yes' );
+			this.removeAttribute( 'error' );
+		} else {
+			this.removeAttribute( 'valid' );
+			this.setAttribute( 'error', error );
+		}
+
+		// Return validity.
+		return valid;
+	}
+
+	/**
+	 * Set the error message.
+	 *
+	 * @param {string} message Error message.
+	 */
+	setErrorMessage( message: string = '' ): void {
+		const error: TPFormErrorElement | null = this.querySelector( 'tp-form-error' );
+		if ( error ) {
+			error.innerHTML = message;
+		} else {
+			const errorElement: TPFormErrorElement = document.createElement( 'tp-form-error' );
+			errorElement.innerHTML = message;
+			this.appendChild( errorElement );
+		}
+
+		this.dispatchEvent( new CustomEvent( 'validation-error', { bubbles: true } ) );
+	}
+
+	/**
+	 * Remove the error message.
+	 */
+	removeErrorMessage(): void {
+		this.querySelector( 'tp-form-error' )?.remove();
+		this.dispatchEvent( new CustomEvent( 'validation-success', { bubbles: true } ) );
+	}
+}
diff --git a/src/form/tp-form-submit.ts b/src/form/tp-form-submit.ts
@@ -0,0 +1,53 @@
+/**
+ * TP Form Submit.
+ */
+export class TPFormSubmitElement extends HTMLElement {
+	/**
+	 * Get observed attributes.
+	 *
+	 * @return {Array} List of observed attributes.
+	 */
+	static get observedAttributes(): string[] {
+		return [ 'submitting-text', 'original-text', 'submitting' ];
+	}
+
+	/**
+	 * Attribute changed callback.
+	 *
+	 * @param {string} _name    Attribute name.
+	 * @param {string} oldValue Old value.
+	 * @param {string} newValue New value.
+	 */
+	attributeChangedCallback( _name: string = '', oldValue: string = '', newValue: string = '' ): void {
+		if ( oldValue !== newValue ) {
+			this.update();
+		}
+	}
+
+	/**
+	 * Update this component.
+	 */
+	update(): void {
+		// Get submit button.
+		const submitButton: HTMLButtonElement | null = this.querySelector( 'button[type="submit"]' );
+		if ( ! submitButton ) {
+			return;
+		}
+
+		// Prepare submit button text.
+		const submittingText: string = this.getAttribute( 'submitting-text' ) ?? '';
+		const originalText: string = this.getAttribute( 'original-text' ) ?? submitButton.innerHTML;
+
+		// Check if we are submitting.
+		if ( 'yes' === this.getAttribute( 'submitting' ) ) {
+			submitButton.setAttribute( 'disabled', 'disabled' );
+			this.setAttribute( 'original-text', originalText );
+			submitButton.innerHTML = submittingText;
+		} else {
+			submitButton.removeAttribute( 'disabled' );
+			this.removeAttribute( 'submitting' );
+			this.removeAttribute( 'original-text' );
+			submitButton.innerHTML = originalText;
+		}
+	}
+}