yew/website/docs/concepts/html/classes.mdx

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---
title: 'Classes'
description: 'A handy macro to handle classes'
---
import Tabs from '@theme/Tabs'
import TabItem from '@theme/TabItem'
## Classes
The struct `Classes` can be used to deal with HTML classes.
When pushing a string to the set, `Classes` ensures that there is one element
for every class even if a single string might contain multiple classes.
`Classes` can also be merged by using `Extend` (i.e.
`classes1.extend(classes2)`) or `push()` (i.e. `classes1.push(classes2)`).
Any type that implements `Into<Classes>` can be pushed onto an existing `Classes`.
The macro `classes!` is a convenient macro that creates one single `Classes`.
Its input accepts a comma-separated list of expressions. The only requirement
is that every expression implements `Into<Classes>`.
<Tabs>
<TabItem value="Literal" label="Literal">
```rust
use yew::{classes, html};
html! {
<div class={classes!("container")}></div>
};
```
</TabItem>
<TabItem value="Multiple" label="Multiple">
```rust
use yew::{classes, html};
html! {
<div class={classes!("class-1", "class-2")}></div>
};
```
</TabItem>
<TabItem value="String" label="String">
```rust
use yew::{classes, html};
let my_classes = String::from("class-1 class-2");
html! {
<div class={classes!(my_classes)}></div>
};
```
</TabItem>
<TabItem value="Optional" label="Optional">
```rust
use yew::{classes, html};
html! {
<div class={classes!(Some("class"))} />
};
```
</TabItem>
<TabItem value="Vector" label="Vector">
```rust
use yew::{classes, html};
html! {
<div class={classes!(vec!["class-1", "class-2"])}></div>
};
```
</TabItem>
<TabItem value="Array" label="Array">
```rust
use yew::{classes, html};
html! {
<div class={classes!(["class-1", "class-2"])}></div>
};
```
</TabItem>
</Tabs>
## Components that accept classes
```rust
use yew::prelude::*;
#[derive(PartialEq, Properties)]
struct Props {
#[prop_or_default]
class: Classes,
fill: bool,
children: Html,
}
#[function_component]
fn MyComponent(props: &Props) -> Html {
let Props {
class,
fill,
children,
} = props;
html! {
<div
class={classes!(
"my-container-class",
fill.then(|| Some("my-fill-class")),
class.clone(),
)}
>
{ children.clone() }
</div>
}
}
```