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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(crate) use scope::ComponentUpdate; pub use scope::Scope; use crate::callback::Callback; use crate::virtual_dom::{VChild, VList, VNode}; use std::any::TypeId; use std::cell::RefCell; use std::fmt; use std::rc::Rc; use stdweb::unstable::TryFrom; use stdweb::web::Node; #[cfg(all(target_arch = "wasm32", not(cargo_web)))] use std::future::Future; /// This type indicates that component should be rendered again. pub type ShouldRender = bool; /// An interface of a UI-component. Uses `self` as a model. pub trait Component: Sized + 'static { /// Control message type which `update` loop get. type Message: 'static; /// Properties type of component implementation. type Properties: Properties; /// Initialization routine which could use a context. fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self; /// Called after the component has been attached to the VDOM and it is safe to receive messages /// from agents but before the browser updates the screen. If true is returned, the view will /// be re-rendered and the user will not see the initial render. fn mounted(&mut self) -> ShouldRender { false } /// Called everytime when a messages of `Msg` type received. It also takes a /// reference to a context. fn update(&mut self, msg: Self::Message) -> ShouldRender; /// Called when the component's parent component re-renders and the /// component's place in the DOM tree remains unchanged. If the component's /// place in the DOM tree changes, calling this method is unnecessary as the /// component is recreated from scratch. It defaults to true if not implemented /// and Self::Properties is not the unit type `()`. fn change(&mut self, _props: Self::Properties) -> ShouldRender { TypeId::of::<Self::Properties>() != TypeId::of::<()>() } /// Called by rendering loop. fn view(&self) -> Html<Self>; /// Called for finalization on the final point of the component's lifetime. fn destroy(&mut self) {} // TODO Replace with `Drop` } /// A type which expected as a result of `view` function implementation. pub type Html<MSG> = VNode<MSG>; /// 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(Properties)] ///# struct WrapperProps { ///# children: Children<Wrapper>, ///# } ///# 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!()} ///# // This is not a valid implementation. This is done for space convenience. ///# fn view(&self) -> Html<Self> { /// 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, Renderable, Component, ComponentLink, html}; /// #[derive(Properties)] /// struct WrapperProps { /// children: Children<Wrapper>, /// } /// ///# 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 view(&self) -> Html<Wrapper> { /// html! { /// <div id="container"> /// { self.props.children.render() } /// </div> /// } /// } /// } /// ``` pub type Children<T> = ChildrenRenderer<Html<T>>; /// 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(Properties)] ///# struct ListProps { ///# children: ChildrenWithProps<ListItem, List>, ///# } ///# 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 view(&self) -> Html<List> {unimplemented!()} ///# } ///# #[derive(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 view(&self) -> Html<Self> {unimplemented!()} ///# } ///# fn view() -> Html<List> { /// 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(Properties)] /// struct ListProps { /// children: ChildrenWithProps<ListItem, List>, /// } /// ///# 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 view(&self) -> Html<Self> { /// html!{{ /// for self.props.children.iter().map(|mut item| { /// item.props.value = format!("item-{}", item.props.value); /// item /// }) /// }} /// } /// } ///# ///# #[derive(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 view(&self) -> Html<ListItem> {unimplemented!()} ///# } /// ``` pub type ChildrenWithProps<C, P> = ChildrenRenderer<VChild<C, P>>; /// A type used for rendering children html. pub struct ChildrenRenderer<T> { len: usize, boxed_render: Box<dyn Fn() -> Vec<T>>, } impl<T> ChildrenRenderer<T> { /// Create children pub fn new(len: usize, boxed_render: Box<dyn Fn() -> Vec<T>>) -> Self { Self { len, boxed_render } } /// Children list is empty pub fn is_empty(&self) -> bool { self.len == 0 } /// Number of children elements pub fn len(&self) -> usize { self.len } /// Build children components and return `Vec` pub fn to_vec(&self) -> Vec<T> { (&self.boxed_render)() } /// Render children components and return `Iterator` pub fn iter(&self) -> impl Iterator<Item = T> { (&self.boxed_render)().into_iter() } } impl<T> Default for ChildrenRenderer<T> { fn default() -> Self { // False positive: https://github.com/rust-lang/rust-clippy/issues/4002 #[allow(clippy::redundant_closure)] let boxed_render = Box::new(|| Vec::new()); Self { len: 0, boxed_render, } } } impl<T> fmt::Debug for ChildrenRenderer<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str("ChildrenRenderer<_>") } } impl<T, COMP: Component> Renderable<COMP> for ChildrenRenderer<T> where T: Into<VNode<COMP>>, { fn render(&self) -> Html<COMP> { VList { children: self.iter().map(|c| c.into()).collect(), } .into() } } /// Wrapped Node reference for later use in Component lifecycle methods. /// /// # Example /// Focus an `<input>` element on mount. /// ``` /// use stdweb::web::html_element::InputElement; /// use stdweb::web::IHtmlElement; ///# use yew::*; /// /// 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 mounted(&mut self) -> ShouldRender { /// if let Some(input) = self.node_ref.try_into::<InputElement>() { /// input.focus(); /// } /// false /// } /// /// fn update(&mut self, _: Self::Message) -> ShouldRender { /// false /// } /// /// fn view(&self) -> Html<Self> { /// html! { /// <input ref=self.node_ref.clone() type="text" /> /// } /// } /// } #[derive(PartialEq, Debug, Default, Clone)] pub struct NodeRef(Rc<RefCell<Option<Node>>>); impl NodeRef { /// Get the wrapped Node reference if it exists pub fn get(&self) -> Option<Node> { self.0.borrow().clone() } /// Try converting the node reference into another form pub fn try_into<INTO: TryFrom<Node>>(&self) -> Option<INTO> { self.get().and_then(|node| INTO::try_from(node).ok()) } /// Place a Node in a reference for later use pub(crate) fn set(&self, node: Option<Node>) { *self.0.borrow_mut() = node; } } /// Should be rendered relative to context and component environment. pub trait Renderable<COMP: Component> { /// Called by rendering loop. fn render(&self) -> Html<COMP>; } impl<COMP: Component> Renderable<COMP> for COMP { fn render(&self) -> Html<COMP> { self.view() } } /// Trait for building properties for a component pub trait Properties { /// 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)] 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 struct ComponentLink<COMP: Component> { scope: Scope<COMP>, } impl<COMP> ComponentLink<COMP> where COMP: Component, { /// Create link for a scope. fn connect(scope: &Scope<COMP>) -> Self { ComponentLink { scope: scope.clone(), } } /// This method sends batch of messages back to the component's loop when the /// returned callback is called. pub fn send_back_batch<F, IN>(&mut self, function: F) -> Callback<IN> where F: Fn(IN) -> Vec<COMP::Message> + 'static, { let scope = self.scope.clone(); let closure = move |input| { let messages = function(input); scope.clone().send_message_batch(messages); }; closure.into() } /// This method sends messages back to the component's loop when the returned callback is called. pub fn send_back<F, IN>(&mut self, function: F) -> Callback<IN> where F: Fn(IN) -> COMP::Message + 'static, { let scope = self.scope.clone(); let closure = move |input| { let output = function(input); scope.clone().send_message(output); }; closure.into() } #[cfg(all(target_arch = "wasm32", not(cargo_web)))] /// This method processes a Future that returns a message and sends it back to the component's /// loop. /// /// # Panics /// If the future panics, then the promise will not resolve, and will leak. pub fn send_future<F>(&self, future: F) where F: Future<Output = COMP::Message> + 'static, { use wasm_bindgen::JsValue; use wasm_bindgen_futures::future_to_promise; let mut scope = self.scope.clone(); let js_future = async { let message: COMP::Message = future.await; // Force movement of the cloned scope into the async block. let scope_send = move || scope.send_message(message); scope_send(); Ok(JsValue::NULL) }; future_to_promise(js_future); } /// This method sends a message to this component to be processed immediately after the /// component has been updated and/or rendered. pub fn send_self(&mut self, msg: COMP::Message) { self.scope.send_message(msg); } } impl<COMP: Component> fmt::Debug for ComponentLink<COMP> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str("ComponentLink<_>") } } /// 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() } }