Created
March 3, 2023 19:30
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>Dice - Web Component</title> | |
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> | |
| <style type="text/css"> | |
| body { | |
| margin: 0 auto; | |
| max-width: 40em; | |
| width: 88%; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <h1>Dice - Web Component</h1> | |
| <roll-dice></roll-dice> | |
| <script> | |
| //Extend the HTMLElement to create the web component | |
| class RollDice extends HTMLElement { | |
| /** | |
| * The class constructor object | |
| */ | |
| constructor () { | |
| //Always call super first in constructor | |
| super(); | |
| const btnText = this.innerHTML.trim(); | |
| this.innerHTML = `<p> | |
| <button>${btnText ? btnText : 'Roll Dice'}</button> | |
| </p> | |
| <div aria-live="polite"></div> | |
| ` | |
| } | |
| /** | |
| * Handle click events | |
| * @param {Event} event The event object | |
| */ | |
| clickHandler (event) { | |
| //get host element | |
| let host = event.target.closest('roll-dice'); | |
| //now get the element to update in the DOM. | |
| let updateRegion = host.querySelector('[aria-live=polite]'); | |
| // array of dice values | |
| let diceSides = [1,2,3,4,5,6]; | |
| if (!updateRegion) return; | |
| //update the Text into the DOM to display the first value | |
| updateRegion.textContent = `You rolled a ${RollDice.#shuffle(diceSides)[0]}`; | |
| } | |
| /* | |
| * This by convention should be called after the UI is loaded | |
| * Runs each time the element is appended to or moved in the DOM | |
| */ | |
| connectedCallback () { | |
| // Attach a click event listener to the button | |
| let btn = this.querySelector('button'); | |
| if (!btn) return; | |
| btn.addEventListener('click', this.clickHandler); | |
| } | |
| /** | |
| * Randomly shuffle an array | |
| * https://stackoverflow.com/a/2450976/1293256 | |
| * @param {Array} array The array to shuffle | |
| * @return {Array} The shuffled array | |
| */ | |
| static #shuffle (array) { | |
| let currentIndex = array.length; | |
| let temporaryValue, randomIndex; | |
| // While there remain elements to shuffle... | |
| while (0 !== currentIndex) { | |
| // Pick a remaining element... | |
| randomIndex = Math.floor(Math.random() * currentIndex); | |
| currentIndex -= 1; | |
| // And swap it with the current element. | |
| temporaryValue = array[currentIndex]; | |
| array[currentIndex] = array[randomIndex]; | |
| array[randomIndex] = temporaryValue; | |
| } | |
| return array; | |
| } | |
| } | |
| if ('customElements' in window) { | |
| customElements.define('roll-dice', RollDice); | |
| } | |
| </script> | |
| </body> | |
| </html> |
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