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//! Component children module
use crate::html::Html;
use crate::virtual_dom::{VChild, VNode};
use std::fmt;
/// A type used for accepting children elements in Component::Properties.
///
/// # Example
/// **`model.rs`**
///
/// In this example, the `Wrapper` component is used to wrap other elements.
/// ```
///# use yew::{Children, Html, Properties, Component, Context, html};
///# #[derive(Clone, Properties, PartialEq)]
///# struct WrapperProps {
///# children: Children,
///# }
///# struct Wrapper;
///# impl Component for Wrapper {
///# type Message = ();
///# type Properties = WrapperProps;
///# fn create(ctx: &Context<Self>) -> Self { Self }
///# fn view(&self, ctx: &Context<Self>) -> Html {
/// html! {
/// <Wrapper>
/// <h4>{ "Hi" }</h4>
/// <div>{ "Hello" }</div>
/// </Wrapper>
/// }
///# }
///# }
/// ```
///
/// **`wrapper.rs`**
///
/// The Wrapper component must define a `children` property in order to wrap other elements. The
/// children property can be used to render the wrapped elements.
/// ```
///# use yew::{Children, Html, Properties, Component, Context, html};
/// #[derive(Clone, Properties, PartialEq)]
/// struct WrapperProps {
/// children: Children,
/// }
///
///# struct Wrapper;
/// impl Component for Wrapper {
/// // ...
///# type Message = ();
///# type Properties = WrapperProps;
/// # fn create(ctx: &Context<Self>) -> Self { Self }
/// fn view(&self, ctx: &Context<Self>) -> Html {
/// html! {
/// <div id="container">
/// { ctx.props().children.clone() }
/// </div>
/// }
/// }
/// }
/// ```
pub type Children = ChildrenRenderer<Html>;
/// A type used for accepting children elements in Component::Properties and accessing their props.
///
/// # Example
/// **`model.rs`**
///
/// In this example, the `List` component can wrap `ListItem` components.
/// ```
///# use yew::{html, Component, Html, Context, ChildrenWithProps, Properties};
///#
///# #[derive(Clone, Properties, PartialEq)]
///# struct ListProps {
///# children: ChildrenWithProps<ListItem>,
///# }
///# struct List;
///# impl Component for List {
///# type Message = ();
///# type Properties = ListProps;
/// # fn create(ctx: &Context<Self>) -> Self { Self }
/// # fn view(&self, ctx: &Context<Self>) -> Html { unimplemented!() }
///# }
///# #[derive(Clone, Properties, PartialEq)]
///# struct ListItemProps {
///# value: String
///# }
///# struct ListItem;
///# impl Component for ListItem {
///# type Message = ();
///# type Properties = ListItemProps;
/// # fn create(ctx: &Context<Self>) -> Self { Self }
/// # fn view(&self, ctx: &Context<Self>) -> Html { unimplemented!() }
///# }
///# fn view() -> Html {
/// html!{
/// <List>
/// <ListItem value="a" />
/// <ListItem value="b" />
/// <ListItem value="c" />
/// </List>
/// }
///# }
/// ```
///
/// **`list.rs`**
///
/// The `List` component must define a `children` property in order to wrap the list items. The
/// `children` property can be used to filter, mutate, and render the items.
/// ```
///# use yew::{html, Component, Html, ChildrenWithProps, Context, Properties};
///# use std::rc::Rc;
///#
/// #[derive(Clone, Properties, PartialEq)]
/// struct ListProps {
/// children: ChildrenWithProps<ListItem>,
/// }
///
///# struct List;
/// impl Component for List {
///# type Message = ();
///# type Properties = ListProps;
///# fn create(ctx: &Context<Self>) -> Self { Self }
///# fn view(&self, ctx: &Context<Self>) -> Html {
/// html!{{
/// for ctx.props().children.iter().map(|mut item| {
/// let mut props = Rc::make_mut(&mut item.props);
/// props.value = format!("item-{}", props.value);
/// item
/// })
/// }}
/// }
/// }
///#
///# #[derive(Clone, Properties, PartialEq)]
///# struct ListItemProps {
///# #[prop_or_default]
///# value: String
///# }
///#
///# struct ListItem;
///# impl Component for ListItem {
///# type Message = ();
///# type Properties = ListItemProps;
///# fn create(ctx: &Context<Self>) -> Self { Self }
///# fn view(&self, ctx: &Context<Self>) -> Html { unimplemented!() }
///# }
/// ```
pub type ChildrenWithProps<CHILD> = ChildrenRenderer<VChild<CHILD>>;
/// A type used for rendering children html.
#[derive(Clone)]
pub struct ChildrenRenderer<T> {
children: Vec<T>,
}
impl<T: PartialEq> PartialEq for ChildrenRenderer<T> {
fn eq(&self, other: &Self) -> bool {
self.children == other.children
}
}
impl<T> ChildrenRenderer<T>
where
T: Clone + Into<VNode>,
{
/// Create children
pub fn new(children: Vec<T>) -> Self {
Self { children }
}
/// Children list is empty
pub fn is_empty(&self) -> bool {
self.children.is_empty()
}
/// Number of children elements
pub fn len(&self) -> usize {
self.children.len()
}
/// Render children components and return `Iterator`
pub fn iter(&self) -> impl Iterator<Item = T> + '_ {
// clone each child lazily.
// This way `self.iter().next()` only has to clone a single node.
self.children.iter().cloned()
}
}
impl<T> Default for ChildrenRenderer<T> {
fn default() -> Self {
Self {
children: Vec::new(),
}
}
}
impl<T> fmt::Debug for ChildrenRenderer<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("ChildrenRenderer<_>")
}
}
impl<T> IntoIterator for ChildrenRenderer<T> {
type Item = T;
type IntoIter = std::vec::IntoIter<Self::Item>;
fn into_iter(self) -> Self::IntoIter {
self.children.into_iter()
}
}