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

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---
title: 'Components'
description: 'Create complex layouts with component hierarchies'
---
## Basic
Components can be used in the `html!` macro:
```rust
use yew::prelude::*;
#[function_component]
fn MyComponent() -> Html {
html! {
{ "This component has no properties!" }
}
}
#[derive(Clone, PartialEq, Properties)]
struct Props {
user_first_name: String,
user_last_name: String,
}
#[function_component]
fn MyComponentWithProps(props: &Props) -> Html {
let Props { user_first_name, user_last_name } = props;
html! {
<>{"user_first_name: "}{user_first_name}{" and user_last_name: "}{user_last_name}</>
}
}
let props = Props {
user_first_name: "Bob".to_owned(),
user_last_name: "Smith".to_owned(),
};
html!{
<>
// No properties
<MyComponent />
// With Properties
<MyComponentWithProps user_first_name="Sam" user_last_name="Idle" />
// With the whole set of props provided at once
<MyComponentWithProps ..props.clone() />
// With Properties from a variable and specific values overridden
<MyComponentWithProps user_last_name="Elm" ..props />
</>
};
```
## Nested
Components can accept child components/elements if they have a `children` field in their `Properties`
```rust title="parent.rs"
use yew::prelude::*;
#[derive(PartialEq, Properties)]
struct Props {
id: String,
children: Html,
}
#[function_component]
fn Container(props: &Props) -> Html {
html! {
<div id={props.id.clone()}>
{ props.children.clone() }
</div>
}
}
html! {
<Container id="container">
<h4>{ "Hi" }</h4>
<div>{ "Hello" }</div>
</Container>
};
```
The `html!` macro allows you to pass a base expression with the `..props` syntax instead of specifying each property individually,
similar to Rust's [Functional Update Syntax](https://doc.rust-lang.org/stable/reference/expressions/struct-expr.html#functional-update-syntax).
This base expression must occur after any individual props are passed.
When passing a base props expression with a `children` field, the children passed in the `html!` macro overwrite the ones already present in the props.
```rust
use yew::prelude::*;
#[derive(PartialEq, Properties)]
struct Props {
id: String,
children: Html,
}
#[function_component]
fn Container(props: &Props) -> Html {
html! {
<div id={props.id.clone()}>
{ props.children.clone() }
</div>
}
}
let props = yew::props!(Props {
id: "container-2",
children: Html::default(),
});
html! {
<Container ..props>
// props.children will be overwritten with this
<span>{ "I am a child, as you can see" }</span>
</Container>
};
```
## Relevant examples
- [Function Todo MVC](https://github.com/yewstack/yew/tree/master/examples/function_todomvc)
- [Function Router](https://github.com/yewstack/yew/tree/master/examples/function_router)