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Web component adder
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| class Adder extends HTMLElement { | |
| constructor() { | |
| super() | |
| this.elements = getXElements(this) | |
| this.addEventListener('input', this) | |
| } | |
| handleEvent(event) { | |
| handleEvent(this, event) | |
| } | |
| add() { | |
| let num1 = +this.elements.num1.value | |
| let num2 = +this.elements.num2.value | |
| this.elements.target.textContent = `${num1} + ${num2} = ${num1 + num2}` | |
| } | |
| } | |
| customElements.define('x-adder', Adder) | |
| function getXElements(fragment) { | |
| let o = {} | |
| for (let el of fragment.querySelectorAll(`[x]`)) { | |
| o[el.getAttribute('x') || ''] = el | |
| el.removeAttribute('x') | |
| } | |
| return o | |
| } | |
| function handleEvent(context, event) { | |
| event.stopPropagation() | |
| event.preventDefault() | |
| let target = event.target | |
| if (target instanceof HTMLElement) { | |
| // @ts-ignore | |
| let action = target.dataset.action || target.closest('[data-action]')?.dataset?.action | |
| if (action) { | |
| if (context[action] instanceof Function) { | |
| requestAnimationFrame(() => { | |
| context[action](event) | |
| }) | |
| } else { | |
| console.error(`Action ${action} not implemented.`) | |
| } | |
| } else if (context[event.type] instanceof Function) { | |
| context[event.type](event) | |
| } | |
| } | |
| } |
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| <!DOCTYPE html> | |
| <html lang="en"> | |
| <head> | |
| <title>Adder</title> | |
| <meta charset="UTF-8"> | |
| <meta name="viewport" content="width=device-width, initial-scale=1"> | |
| </head> | |
| <body> | |
| <h1>Add numbers!</h1> | |
| <x-adder> | |
| <input x=num1 data-action=add type="number"> | |
| <input x=num2 data-action=add type="number"> | |
| <p x=target></p> | |
| </x-adder> | |
| <script type=module src="./adder.js"></script> | |
| </body> | |
| </html> |
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