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Version: 0.18.0

Children

General usage

Most of the time, when allowing a component to have children, you don't care what type of children the component has. In such cases, the below example will suffice.

use yew::{html, Children, Component, Html, Properties};

#[derive(Properties, Clone)]
pub struct ListProps {
#[prop_or_default]
pub children: Children,
}

pub struct List {
props: ListProps,
}

impl Component for List {
type Properties = ListProps;
// ...

fn view(&self) -> Html {
html! {
<div class="list">
{ for self.props.children.iter() }
</div>
}
}
}

Advanced usage

Typed children

In cases where you want one type of component to be passed as children to your component, you can use yew::html::ChildrenWithProps<T>.

use yew::{html, ChildrenWithProps, Component, Html, Properties};

// ...

#[derive(Properties, Clone)]
pub struct ListProps {
#[prop_or_default]
pub children: ChildrenWithProps<Item>,
}

pub struct List {
props: ListProps,
}

impl Component for List {
type Properties = ListProps;
// ...

fn view(&self) -> Html {
html! {
<div class="list">
{ for self.props.children.iter() }
</div>
}
}
}

Enum typed children

Of course, sometimes you might need to restrict the children to a few different components. In these cases, you have to get a little more hands-on with Yew.

The derive_more crate is used here for better ergonomics. If you don't want to use it, you can manually implement From for each variant.

use yew::{
html, html::ChildrenRenderer, virtual_dom::VChild,
Component, Html, Properties
};

// `derive_more::From` implements `From<VChild<Primary>>` and
// `From<VChild<Secondary>>` for `Item` automatically!
#[derive(Clone, derive_more::From)]
pub enum Item {
Primary(VChild<Primary>),
Secondary(VChild<Secondary>),
}

// Now, we implement `Into<Html>` so that yew knows how to render `Item`.
impl Into<Html> for Item {
fn into(self) -> Html {
match self {
Self::Primary(child) => child.into(),
Self::Secondary(child) => child.into(),
}
}
}

#[derive(Properties, Clone)]
pub struct ListProps {
#[prop_or_default]
pub children: ChildrenRenderer<Item>,
}

pub struct List {
props: ListProps,
}

impl Component for List {
type Properties = ListProps;
// ...

fn view(&self) -> Html {
html! {
<div class="list">
{ for self.props.children.iter() }
</div>
}
}
}

Optional typed child

You can also have a single optional child component of a specific type too:

use yew::{html, virtual_dom::VChild, Component, Html, Properties};

#[derive(Clone, Properties)]
pub struct PageProps {
#[prop_or_default]
pub sidebar: Option<VChild<PageSideBar>>,
}

struct Page {
props: PageProps,
}

impl Component for Page {
type Properties = PageProps;
// ...

fn view(&self) -> Html {
html! {
<div class="page">
{ self.props.sidebar.clone().map(Html::from).unwrap_or_default() }
// ... page content
</div>
}
}
}

// The page component can be called either with the sidebar or without:

// Page without sidebar
html! {
<Page />
}

// Page with sidebar
html! {
<Page sidebar=html_nested! {
<PageSideBar />
} />
}