Add custom type for attribute values

examples/keyed_list/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2018"
 license = "MIT OR Apache-2.0"
 
 [dependencies]
-fake = "2.2"
+fake = "=2.4.1"
 getrandom = { version = "0.2", features = ["js"] }
 instant = { version = "0.1", features = ["wasm-bindgen"] }
 log = "0.4"
@@ -17,6 +17,6 @@ yew = { path = "../../packages/yew" }
 [dependencies.web-sys]
 version = "0.3"
 features = [
-	"HtmlElement",
-	"HtmlInputElement",
+    "HtmlElement",
+    "HtmlInputElement",
 ]

examples/router/src/pages/post.rs

@@ -1,6 +1,5 @@
 use crate::{content, generator::Generated, Route};
 use content::PostPart;
-use std::borrow::Cow;
 use yew::prelude::*;
 use yew_router::prelude::*;
 
@@ -39,7 +38,7 @@ impl Component for Post {
         html! {
             <>
                 <section class="hero is-medium is-light has-background">
-                    <img class="hero-background is-transparent" src={Cow::Owned(post.meta.image_url.clone())} />
+                    <img class="hero-background is-transparent" src={post.meta.image_url.clone()} />
                     <div class="hero-body">
                         <div class="container">
                             <h1 class="title">
@@ -70,7 +69,7 @@ impl Post {
             <article class="media block box my-6">
                 <figure class="media-left">
                     <p class="image is-64x64">
-                        <img src={Cow::Owned(quote.author.image_url.clone())} loading="lazy" />
+                        <img src={quote.author.image_url.clone()} loading="lazy" />
                     </p>
                 </figure>
                 <div class="media-content">
@@ -90,7 +89,7 @@ impl Post {
     fn render_section_hero(&self, section: &content::Section) -> Html {
         html! {
             <section class="hero is-dark has-background mt-6 mb-3">
-                <img class="hero-background is-transparent" src={Cow::Owned(section.image_url.clone())} loading="lazy" />
+                <img class="hero-background is-transparent" src={section.image_url.clone()} loading="lazy" />
                 <div class="hero-body">
                     <div class="container">
                         <h2 class="subtitle">{ &section.title }</h2>

packages/yew-macro/src/html_tree/html_element.rs

@@ -168,7 +168,7 @@ impl ToTokens for HtmlElement {
                         expr => Value::Dynamic(quote_spanned! {expr.span()=>
                             if #expr {
                                 ::std::option::Option::Some(
-                                    ::std::borrow::Cow::<'static, ::std::primitive::str>::Borrowed(#key)
+                                    ::yew::virtual_dom::AttrValue::Static(#key)
                                 )
                             } else {
                                 ::std::option::Option::None

packages/yew-macro/src/stringify.rs

@@ -6,17 +6,17 @@ use syn::{Expr, Lit, LitStr};
 /// Stringify a value at runtime.
 fn stringify_at_runtime(src: impl ToTokens) -> TokenStream {
     quote_spanned! {src.span()=>
-        ::std::convert::Into::<::std::borrow::Cow::<'static, ::std::primitive::str>>::into(#src)
+        ::std::convert::Into::<::yew::virtual_dom::AttrValue>::into(#src)
     }
 }
 
-/// Create `Cow<'static, str>` construction calls.
+/// Create `AttrValue` construction calls.
 ///
 /// This is deliberately not implemented for strings to preserve spans.
 pub trait Stringify {
     /// Try to turn the value into a string literal.
     fn try_into_lit(&self) -> Option<LitStr>;
-    /// Create `Cow<'static, str>` however possible.
+    /// Create `AttrValue` however possible.
     fn stringify(&self) -> TokenStream;
 
     /// Optimize literals to `&'static str`, otherwise keep the value as is.
@@ -71,7 +71,7 @@ impl Stringify for LitStr {
 
     fn stringify(&self) -> TokenStream {
         quote_spanned! {self.span()=>
-            ::std::borrow::Cow::<'static, ::std::primitive::str>::Borrowed(#self)
+            ::yew::virtual_dom::AttrValue::Static(#self)
         }
     }
 }

packages/yew-macro/tests/html_macro/component-fail.stderr

@@ -342,8 +342,8 @@ error[E0277]: the trait bound `{integer}: IntoPropValue<String>` is not satisfie
    |                                 ^ the trait `IntoPropValue<String>` is not implemented for `{integer}`
    |
    = help: the following implementations were found:
-             <&'static str as IntoPropValue<Cow<'static, str>>>
-             <&'static str as IntoPropValue<Option<Cow<'static, str>>>>
+             <&'static str as IntoPropValue<AttrValue>>
+             <&'static str as IntoPropValue<Option<AttrValue>>>
              <&'static str as IntoPropValue<Option<String>>>
              <&'static str as IntoPropValue<String>>
            and 11 others
@@ -355,8 +355,8 @@ error[E0277]: the trait bound `{integer}: IntoPropValue<String>` is not satisfie
    |                                  ^ the trait `IntoPropValue<String>` is not implemented for `{integer}`
    |
    = help: the following implementations were found:
-             <&'static str as IntoPropValue<Cow<'static, str>>>
-             <&'static str as IntoPropValue<Option<Cow<'static, str>>>>
+             <&'static str as IntoPropValue<AttrValue>>
+             <&'static str as IntoPropValue<Option<AttrValue>>>
              <&'static str as IntoPropValue<Option<String>>>
              <&'static str as IntoPropValue<String>>
            and 11 others