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)`). In
fact, anything that implements `Into<Classes>` can be used to push new classes
to the set.
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};
let my_classes = ["class-1", "class-2"];
html! {
<div class={classes!(my_classes.as_ref())}></div>
};
```
</TabItem>
</Tabs>
## Components that accept classes
```rust
use yew::{
classes, html, Children, Classes, Component,
Context, Html, Properties
};
#[derive(PartialEq, Properties)]
struct Props {
#[prop_or_default]
class: Classes,
fill: bool,
children: Children,
}
struct MyComponent;
impl Component for MyComponent {
type Message = ();
type Properties = Props;
fn create(_ctx: &Context<Self>) -> Self {
Self
}
fn view(&self, ctx: &Context<Self>) -> Html {
let Props {
class,
fill,
children,
} = &ctx.props();
html! {
<div
class={classes!(
"my-container-class",
fill.then(|| Some("my-fill-class")),
class.clone(),
)}
>
{ children.clone() }
</div>
}
}
}
```