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Advanced Techniques

Manual UI Updates

If you have a more simple UI component, you can combine the signal() method with the Element.addEventListener() to manually update your UI instead of using the render() function.

For example, imagine you have an element that displays the number of items in a shopping cart.

Cart (<span id="cart-items">0</span>)

Rather than diffing the DOM every time that number of items changes, you can listen for data updates and use the Element.textContent property to manually update the UI. It will be faster and simpler.

// Get the cart element
let cartCount = document.querySelector('#cart-items');

// Create a reactive store
let cart = signal([], 'cart');

// Update how many cart items are displayed in the UI
document.addEventListener('reef:signal-cart', function () {
	cartCount.textContent = cart.length;

// Add an item to the cart
// The UI will automatically be updated
	item: 'T-Shirt',
	size: 'M',
	cost: 29

Try manual UI updates on CodePen →