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//! The main module which contents aliases to necessary items //! to create a template and implement `update` and `view` functions. //! Also this module contains declaration of `Component` trait which used //! to create own UI-components. mod listener; mod scope; pub use listener::*; pub use scope::{AnyScope, Scope}; pub(crate) use scope::{ComponentUpdate, Scoped}; use crate::callback::Callback; use crate::virtual_dom::{VChild, VNode}; use cfg_if::cfg_if; use cfg_match::cfg_match; use std::cell::RefCell; use std::fmt; use std::rc::Rc; cfg_if! { if #[cfg(feature = "std_web")] { use stdweb::unstable::TryFrom; use stdweb::web::Node; } else if #[cfg(feature = "web_sys")] { use wasm_bindgen::JsValue; use web_sys::Node; } } /// This type indicates that component should be rendered again. pub type ShouldRender = bool; /// Components are the basic building blocks of the UI in a Yew app. Each Component /// chooses how to display itself using received props and self-managed state. /// Components can be dynamic and interactive by declaring messages that are /// triggered and handled asynchronously. This async update mechanism is inspired by /// Elm and the actor model used in the Actix framework. pub trait Component: Sized + 'static { /// Messages are used to make Components dynamic and interactive. Simple /// Component's can declare their Message type to be `()`. Complex Component's /// commonly use an enum to declare multiple Message types. type Message: 'static; /// Properties are the inputs to a Component and should not mutated within a /// Component. They are passed to a Component using a JSX-style syntax. /// ``` ///# use yew::{Html, Component, Properties, ComponentLink, html}; ///# struct Model; ///# #[derive(Clone, Properties)] ///# struct Props { ///# prop: String, ///# } ///# impl Component for Model { ///# type Message = ();type Properties = Props; ///# fn create(props: Self::Properties,link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self,msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} ///# fn view(&self) -> Html { /// html! { /// <Model prop="value" /> /// } ///# }} /// ``` type Properties: Properties; /// Components are created with their properties as well as a `ComponentLink` which /// can be used to send messages and create callbacks for triggering updates. fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self; /// Components handle messages in their `update` method and commonly use this method /// to update their state and (optionally) re-render themselves. fn update(&mut self, msg: Self::Message) -> ShouldRender; /// When the parent of a Component is re-rendered, it will either be re-created or /// receive new properties in the `change` lifecycle method. Component's can choose /// to re-render if the new properties are different than the previously /// received properties. Most Component's will use props with a `PartialEq` /// impl and will be implemented like this: /// ``` ///# use yew::{Html, Component, ComponentLink, html, ShouldRender}; ///# struct Model{props: ()}; ///# impl Component for Model { ///# type Message = ();type Properties = (); ///# fn create(props: Self::Properties,link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self,msg: Self::Message) -> bool {unimplemented!()} ///# fn view(&self) -> Html {unimplemented!()} /// fn change(&mut self, props: Self::Properties) -> ShouldRender { /// if self.props != props { /// self.props = props; /// true /// } else { /// false /// } /// } ///# } /// ``` /// Components which don't have properties should always return false. fn change(&mut self, _props: Self::Properties) -> ShouldRender; /// Components define their visual layout using a JSX-style syntax through the use of the /// `html!` procedural macro. The full guide to using the macro can be found in [Yew's /// documentation](https://yew.rs/docs/concepts/html). fn view(&self) -> Html; /// The `rendered` method is called after each time a Component is rendered but /// before the browser updates the page. /// ## Examples /// ```rust ///# use yew::{Html, Component, ComponentLink, html, ShouldRender}; ///# struct Model{props: ()}; ///# impl Model { fn setup_element(&self) { } } ///# impl Component for Model { ///# type Message = ();type Properties = (); ///# fn create(props: Self::Properties,link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self,msg: Self::Message) -> bool {unimplemented!()} ///# fn view(&self) -> Html {unimplemented!()} ///# fn change(&mut self, _props: Self::Properties) -> ShouldRender { unimplemented!() } /// fn rendered(&mut self, first_render: bool) { /// if first_render { /// self.setup_element(); // Similar to 'mounted' in other frameworks /// } /// } ///# } fn rendered(&mut self, _first_render: bool) {} /// The `destroy` method is called right before a Component is unmounted. fn destroy(&mut self) {} } /// A type which expected as a result of `view` function implementation. pub type Html = VNode; /// 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, ComponentLink, html}; ///# #[derive(Clone, Properties)] ///# struct WrapperProps { ///# children: Children, ///# } ///# struct Wrapper; ///# impl Component for Wrapper{ ///# type Message = (); ///# type Properties = WrapperProps; ///# fn create(props: Self::Properties,link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self,msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} ///# // This is not a valid implementation. This is done for space convenience. ///# fn view(&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, ComponentLink, html}; /// #[derive(Clone, Properties)] /// struct WrapperProps { /// children: Children, /// } /// ///# struct Wrapper {props: WrapperProps}; /// impl Component for Wrapper { /// // ... ///# type Message = (); ///# type Properties = WrapperProps; ///# fn create(props: Self::Properties,link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self,msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} /// fn view(&self) -> Html { /// html! { /// <div id="container"> /// { self.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, Renderable, Html, ComponentLink, ChildrenWithProps, Properties}; ///# ///# #[derive(Clone, Properties)] ///# struct ListProps { ///# children: ChildrenWithProps<ListItem>, ///# } ///# struct List; ///# impl Component for List { ///# type Message = (); ///# type Properties = ListProps; ///# fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self, msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} ///# fn view(&self) -> Html {unimplemented!()} ///# } ///# #[derive(Clone, Properties)] ///# struct ListItemProps { ///# value: String ///# } ///# struct ListItem; ///# impl Component for ListItem { ///# type Message = (); ///# type Properties = ListItemProps; ///# fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self, msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} ///# fn view(&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, ComponentLink, Properties}; ///# /// #[derive(Clone, Properties)] /// struct ListProps { /// children: ChildrenWithProps<ListItem>, /// } /// ///# struct List {props: ListProps}; /// impl Component for List { ///# type Message = (); ///# type Properties = ListProps; ///# fn create(props: Self::Properties,link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self,msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} /// // ... /// fn view(&self) -> Html { /// html!{{ /// for self.props.children.iter().map(|mut item| { /// item.props.value = format!("item-{}", item.props.value); /// item /// }) /// }} /// } /// } ///# ///# #[derive(Clone, Properties)] ///# struct ListItemProps { ///# #[prop_or_default] ///# value: String ///# } ///# ///# struct ListItem; ///# impl Component for ListItem { ///# type Message = (); ///# type Properties = ListItemProps; ///# fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self {unimplemented!()} ///# fn update(&mut self, msg: Self::Message) -> bool {unimplemented!()} ///# fn change(&mut self, _: Self::Properties) -> bool {unimplemented!()} ///# fn view(&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<'a>(&'a self) -> impl Iterator<Item = T> + 'a { // 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() } } /// Wrapped Node reference for later use in Component lifecycle methods. /// /// # Example /// Focus an `<input>` element on mount. /// ``` /// #[cfg(feature = "std_web")] /// use stdweb::web::{html_element::InputElement, IHtmlElement}; /// #[cfg(feature = "web_sys")] /// use web_sys::HtmlInputElement as InputElement; ///# use yew::prelude::*; /// /// pub struct Input { /// node_ref: NodeRef, /// } /// /// impl Component for Input { /// type Message = (); /// type Properties = (); /// /// fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { /// Input { /// node_ref: NodeRef::default(), /// } /// } /// /// fn rendered(&mut self, first_render: bool) { /// if first_render { /// if let Some(input) = self.node_ref.cast::<InputElement>() { /// input.focus(); /// } /// } /// } /// /// fn change(&mut self, _: Self::Properties) -> ShouldRender { /// false /// } /// /// fn update(&mut self, _: Self::Message) -> ShouldRender { /// false /// } /// /// fn view(&self) -> Html { /// html! { /// <input ref=self.node_ref.clone() type="text" /> /// } /// } /// } #[derive(Debug, Default, Clone)] pub struct NodeRef(Rc<RefCell<NodeRefInner>>); impl PartialEq for NodeRef { fn eq(&self, other: &Self) -> bool { self.0.as_ptr() == other.0.as_ptr() || Some(self) == other.0.borrow().link.as_ref() } } #[derive(PartialEq, Debug, Default, Clone)] struct NodeRefInner { node: Option<Node>, link: Option<NodeRef>, } impl NodeRef { /// Get the wrapped Node reference if it exists pub fn get(&self) -> Option<Node> { let inner = self.0.borrow(); inner.node.clone().or_else(|| inner.link.as_ref()?.get()) } /// Try converting the node reference into another form pub fn cast< #[cfg(feature = "std_web")] INTO: TryFrom<Node>, #[cfg(feature = "web_sys")] INTO: AsRef<Node> + From<JsValue>, >( &self, ) -> Option<INTO> { let node = self.get(); cfg_match! { feature = "std_web" => node.and_then(|node| INTO::try_from(node).ok()), feature = "web_sys" => node.map(Into::into).map(INTO::from), } } /// Wrap an existing `Node` in a `NodeRef` pub(crate) fn new(node: Node) -> Self { let node_ref = NodeRef::default(); node_ref.set(Some(node)); node_ref } /// Place a Node in a reference for later use pub(crate) fn set(&self, node: Option<Node>) { let mut this = self.0.borrow_mut(); this.node = node; this.link = None; } /// Link a downstream `NodeRef` pub(crate) fn link(&self, node_ref: Self) { // Avoid circular references if self == &node_ref { return; } let mut this = self.0.borrow_mut(); this.node = None; this.link = Some(node_ref); } /// Reuse an existing `NodeRef` pub(crate) fn reuse(&self, node_ref: Self) { // Avoid circular references if self == &node_ref { return; } let mut this = self.0.borrow_mut(); let existing = node_ref.0.borrow(); this.node = existing.node.clone(); this.link = existing.link.clone(); } } /// Trait for rendering virtual DOM elements pub trait Renderable { /// Called by rendering loop. fn render(&self) -> Html; } impl<COMP: Component> Renderable for COMP { fn render(&self) -> Html { self.view() } } /// Trait for building properties for a component pub trait Properties: Clone { /// Builder that will be used to construct properties type Builder; /// Entrypoint for building properties fn builder() -> Self::Builder; } /// Builder for when a component has no properties #[derive(Debug)] #[doc(hidden)] pub struct EmptyBuilder; impl Properties for () { type Builder = EmptyBuilder; fn builder() -> Self::Builder { EmptyBuilder } } impl EmptyBuilder { /// Build empty properties pub fn build(self) {} } /// Link to component's scope for creating callbacks. pub type ComponentLink<COMP> = Scope<COMP>; /// A bridging type for checking `href` attribute value. #[derive(Debug)] pub struct Href { link: String, } impl From<String> for Href { fn from(link: String) -> Self { Href { link } } } impl<'a> From<&'a str> for Href { fn from(link: &'a str) -> Self { Href { link: link.to_owned(), } } } impl ToString for Href { fn to_string(&self) -> String { self.link.to_owned() } } #[cfg(test)] mod tests { use super::*; use crate::utils::document; #[cfg(feature = "wasm_test")] use wasm_bindgen_test::{wasm_bindgen_test as test, wasm_bindgen_test_configure}; #[cfg(feature = "wasm_test")] wasm_bindgen_test_configure!(run_in_browser); #[test] fn self_linking_node_ref() { let node: Node = document().create_text_node("test node").into(); let node_ref = NodeRef::new(node.clone()); let node_ref_2 = NodeRef::new(node.clone()); // Link to self node_ref.link(node_ref.clone()); assert_eq!(node, node_ref.get().unwrap()); // Create cycle of two node refs node_ref.link(node_ref_2.clone()); node_ref_2.link(node_ref); assert_eq!(node, node_ref_2.get().unwrap()); } }