feat: attr: and #[prop(attrs)] syntax for passing attributes down to components (#1628)

leptos/src/lib.rs

@@ -265,6 +265,18 @@ pub trait Props {
     fn builder() -> Self::Builder;
 }
 
+#[doc(hidden)]
+pub trait DynAttrs {
+    fn dyn_attrs(self, _args: Vec<(&'static str, Attribute)>) -> Self
+    where
+        Self: Sized,
+    {
+        self
+    }
+}
+
+impl DynAttrs for () {}
+
 #[doc(hidden)]
 pub trait PropsOrNoPropsBuilder {
     type Builder;

leptos_macro/src/component.rs

@@ -332,6 +332,39 @@ impl ToTokens for Model {
             }
         };
 
+        let count = props
+            .iter()
+            .filter(
+                |Prop {
+                     prop_opts: PropOpt { attrs, .. },
+                     ..
+                 }| *attrs,
+            )
+            .count();
+
+        let dyn_attrs_props = props
+            .iter()
+            .filter(
+                |Prop {
+                     prop_opts: PropOpt { attrs, .. },
+                     ..
+                 }| *attrs,
+            )
+            .enumerate()
+            .map(|(idx, Prop { name, .. })| {
+                let ident = &name.ident;
+                if idx < count - 1 {
+                    quote! {
+                        self.#ident = v.clone().into();
+                    }
+                } else {
+                    quote! {
+                        self.#ident = v.into();
+                    }
+                }
+            })
+            .collect::<TokenStream>();
+
         let body = quote! {
             #body
             #destructure_props
@@ -461,6 +494,13 @@ impl ToTokens for Model {
                 }
             }
 
+            impl #impl_generics ::leptos::DynAttrs for #props_name #generics #where_clause {
+                fn dyn_attrs(mut self, v: Vec<(&'static str, ::leptos::Attribute)>) -> Self {
+                    #dyn_attrs_props
+                    self
+                }
+            }
+
             #into_view
 
             #docs
@@ -699,6 +739,7 @@ struct PropOpt {
     #[attribute(example = "5 * 10")]
     default: Option<syn::Expr>,
     into: bool,
+    attrs: bool,
 }
 
 struct TypedBuilderOpts {
@@ -711,7 +752,7 @@ struct TypedBuilderOpts {
 impl TypedBuilderOpts {
     fn from_opts(opts: &PropOpt, is_ty_option: bool) -> Self {
         Self {
-            default: opts.optional || opts.optional_no_strip,
+            default: opts.optional || opts.optional_no_strip || opts.attrs,
             default_with_value: opts.default.clone(),
             strip_option: opts.strip_option || opts.optional && is_ty_option,
             into: opts.into,

leptos_macro/src/view/component_builder.rs

@@ -33,6 +33,7 @@ pub(crate) fn component_to_tokens(
             !attr.key.to_string().starts_with("bind:")
                 && !attr.key.to_string().starts_with("clone:")
                 && !attr.key.to_string().starts_with("on:")
+                && !attr.key.to_string().starts_with("attr:")
         })
         .map(|attr| {
             let name = &attr.key;
@@ -70,6 +71,7 @@ pub(crate) fn component_to_tokens(
         .collect::<Vec<_>>();
 
     let events = attrs
+        .clone()
         .filter(|attr| attr.key.to_string().starts_with("on:"))
         .map(|attr| {
             let (event_type, handler) = event_from_attribute_node(attr, true);
@@ -80,6 +82,24 @@ pub(crate) fn component_to_tokens(
         })
         .collect::<Vec<_>>();
 
+    let dyn_attrs = attrs
+        .filter(|attr| attr.key.to_string().starts_with("attr:"))
+        .filter_map(|attr| {
+            let name = &attr.key.to_string();
+            let name = name.strip_prefix("attr:");
+            let value = attr.value().map(|v| {
+                quote! { #v }
+            })?;
+            Some(quote! { (#name, #value.into_attribute()) })
+        })
+        .collect::<Vec<_>>();
+
+    let dyn_attrs = if dyn_attrs.is_empty() {
+        quote! {}
+    } else {
+        quote! { .dyn_attrs(vec![#(#dyn_attrs),*]) }
+    };
+
     let mut slots = HashMap::new();
     let children = if node.children.is_empty() {
         quote! {}
@@ -163,6 +183,7 @@ pub(crate) fn component_to_tokens(
                 #(#slots)*
                 #children
                 .build()
+                #dyn_attrs
         )
     };
 

leptos_macro/tests/ui/component.stderr

@@ -44,7 +44,7 @@ error: return type is incorrect
   |
   = help: return signature must be `-> impl IntoView`
 
-error: supported fields are `optional`, `optional_no_strip`, `strip_option`, `default` and `into`
+error: supported fields are `optional`, `optional_no_strip`, `strip_option`, `default`, `into` and `attrs`
   --> tests/ui/component.rs:10:31
    |
 10 | fn unknown_prop_option(#[prop(hello)] test: bool) -> impl IntoView {

leptos_macro/tests/ui/component_absolute.stderr

@@ -6,7 +6,7 @@ error: return type is incorrect
   |
   = help: return signature must be `-> impl IntoView`
 
-error: supported fields are `optional`, `optional_no_strip`, `strip_option`, `default` and `into`
+error: supported fields are `optional`, `optional_no_strip`, `strip_option`, `default`, `into` and `attrs`
  --> tests/ui/component_absolute.rs:5:31
   |
 5 | fn unknown_prop_option(#[prop(hello)] test: bool) -> impl ::leptos::IntoView {