use: Directive Syntax
Apply a Svelte action to a DOM element using the use: directive.
use: Directive Syntax is a free Sveltejs Academy lesson on CoddyKit. This is lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Sveltejs Academy learning path, and your progress syncs across the web and the CoddyKit app. The Sveltejs Academy course includes 4 lessons in total.
Actions in Svelte
An action is a function that runs when an element is mounted. It is invoked with the use: directive.
Basic Action
An action receives the DOM node as its argument.
function highlight(node) {
node.style.background = "yellow";
}Apply with use:
Attach the action to any element via use:action.
<p use:highlight>I am highlighted</p>Why Actions
Actions encapsulate imperative DOM behavior (focus, intersection, drag, etc.) for reuse.
No Markup Required
Actions do not render anything; they augment existing elements.
Multiple Actions
You can apply multiple actions to one element with multiple use: directives.
<div use:trap use:scroll>Shipping in Libraries
Many Svelte libraries expose their behavior as actions for ergonomic integration.
Imports
Actions are plain functions; import them like any module.
import { clickOutside } from "$lib/actions";Type Hints
Type actions with the Action<Element, Params> generic from svelte/action.
Lifecycle Awareness
Actions run after mount, so the node exists in the DOM when they execute.
Simple to Powerful
Actions can be as small as a one-liner or as rich as a library wrapper.
Quick Check
How do you attach an action?
Recap
Actions are functions invoked via use:. They receive the DOM node and add imperative behavior.
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Frequently Asked Questions
Is the “use: Directive Syntax” lesson free?
Yes — the full text of “use: Directive Syntax” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Sveltejs Academy course, upgrade to CoddyKit PRO. The Sveltejs Academy course includes 4 lessons in total.
What will I learn in “use: Directive Syntax”?
Apply a Svelte action to a DOM element using the use: directive. You practise Sveltejs Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Sveltejs Academy?
No prior experience is required. Sveltejs Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 1 of 4.
How long does the “use: Directive Syntax” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Sveltejs Academy lesson?
Yes. Every Sveltejs Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- use: Directive Syntax
- Action Parameters and Updates
- The destroy() Cleanup Function
- Practical Actions: clickOutside tooltip autofocus