Julius Lungys 636692507e
Convert components concept docs from SC to FC (#2434)
* Convert components concept docs from SC to FC
- moved struct components to advanced topics
- added docs about HOC for Suspense and Context
- added a ease-in topic before components that introduces
HTML/CSS/JS in yew
- edit components concept to use function components

* translations

* fix todo links

* fix tests

* spelling bee
2022-02-07 11:03:12 +02:00

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---
title: "Refs"
description: "Out-of-band DOM access"
---
The `ref` keyword can be used inside of any HTML element or component to get the DOM `Element` that
the item is attached to. This can be used to make changes to the DOM outside of the `view` lifecycle
method.
This is useful for getting ahold of canvas elements, or scrolling to different sections of a page.
For example, using a `NodeRef` in a component's `rendered` method allows you to make draw calls to
a canvas element after it has been rendered from `view`.
The syntax is:
```rust
use web_sys::Element;
use yew::{html, Component, Context, Html, NodeRef};
struct Comp {
node_ref: NodeRef,
}
impl Component for Comp {
type Message = ();
type Properties = ();
fn create(_ctx: &Context<Self>) -> Self {
Self {
// highlight-next-line
node_ref: NodeRef::default(),
}
}
fn view(&self, _ctx: &Context<Self>) -> Html {
html! {
// highlight-next-line
<div ref={self.node_ref.clone()}></div>
}
}
fn rendered(&mut self, _ctx: &Context<Self>, _first_render: bool) {
// highlight-start
let has_attributes = self.node_ref
.cast::<Element>()
.unwrap()
.has_attributes();
// highlight-end
}
}
```
## Relevant examples
- [Node Refs](https://github.com/yewstack/yew/tree/master/examples/node_refs)