Refactor conditional assign and should render.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bootstrap-rs"
-version = "0.2.13"
+version = "0.3.0"
 authors = ["Thomas Gideon <cmdln@thecommandline.net>"]
 edition = "2018"
 

src/alert/mod.rs

@@ -27,7 +27,7 @@ impl Component for Alert {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/breadcrumb/item.rs

@@ -49,7 +49,7 @@ impl Component for BreadcrumbItem {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/breadcrumb/mod.rs

@@ -21,7 +21,7 @@ impl Component for Breadcrumb {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/button/group.rs

@@ -1,4 +1,4 @@
-use crate::{prelude::render_on_change, props::Props, render};
+use crate::{prelude::*, props::Props, render};
 use yew::prelude::*;
 
 pub struct ButtonGroup {
@@ -18,7 +18,7 @@ impl Component for ButtonGroup {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/button/mod.rs

@@ -4,7 +4,7 @@ mod toolbar;
 
 use self::props::Props;
 pub use self::{group::ButtonGroup, toolbar::ButtonToolbar};
-use crate::{prelude::render_on_change, render};
+use crate::{prelude::*, render};
 use std::fmt::{Display, Formatter, Result};
 use yew::prelude::*;
 
@@ -51,7 +51,7 @@ impl Component for Button {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/button/toolbar.rs

@@ -1,4 +1,4 @@
-use crate::{prelude::render_on_change, props::Props, render};
+use crate::{prelude::*, props::Props, render};
 use yew::prelude::*;
 
 pub struct ButtonToolbar {
@@ -18,7 +18,7 @@ impl Component for ButtonToolbar {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/card/body.rs

@@ -18,7 +18,7 @@ impl Component for CardBody {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/card/header.rs

@@ -18,7 +18,7 @@ impl Component for CardHeader {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/card/mod.rs

@@ -23,7 +23,7 @@ impl Component for Card {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/card/text.rs

@@ -18,7 +18,7 @@ impl Component for CardText {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/container.rs

@@ -18,7 +18,7 @@ impl Component for Container {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/form/mod.rs

@@ -18,7 +18,7 @@ impl Component for FormGroup {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/input/group.rs

@@ -18,7 +18,7 @@ impl Component for InputGroup {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/input/mod.rs

@@ -61,7 +61,7 @@ impl Component for Input {
         if self.props.value != props.value {
             self.state = props.value.clone();
         }
-        render_on_change(&mut self.props, props)
+        render_if_ne(&mut self.props, props)
     }
 
     fn view(&self) -> Html {

src/input/textarea.rs

@@ -31,7 +31,7 @@ impl Component for TextArea {
     }
 
     fn change(&mut self, props: Self::Properties) -> ShouldRender {
-        let should_render = render_on_change(&mut self.props, props);
+        let should_render = render_if_ne(&mut self.props, props);
         if should_render {
             self.state = extract_state(&self.props);
         }

src/prelude/mod.rs

@@ -7,15 +7,29 @@ mod padding;
 pub use self::{border::Border, color::Color, edge::Edge, margin::Margin, padding::Padding};
 use yew::prelude::*;
 
-pub fn render_on_change<P: Properties + PartialEq>(
+pub fn render_if_ne<T: PartialEq>(assign_to: &mut T, argument: T) -> ShouldRender {
-    props_on_comp: &mut P,
+    render_if(assign_to, argument, identity, is_ne)
-    props: P,
+}
+
+pub fn render_if_opt_str<S: AsRef<str>>(
+    assign_to: &mut Option<String>,
+    argument: S,
 ) -> ShouldRender {
-    if props_on_comp == &props {
+    render_if(assign_to, argument, opt_from_str, is_ne)
-        false
+}
-    } else {
+
-        *props_on_comp = props;
+pub fn render_if<T, A>(
+    assign_to: &mut T,
+    argument: A,
+    map: impl Fn(A) -> T,
+    assign_render: impl Fn(&mut T, &T) -> bool,
+) -> ShouldRender {
+    let argument = map(argument);
+    if assign_render(assign_to, &argument) {
+        *assign_to = argument;
         true
+    } else {
+        false
     }
 }
 
@@ -26,3 +40,48 @@ pub fn valid_as_class(v: &Option<bool>) -> &'static str {
         Some(false) => " is-invalid",
     }
 }
+
+fn identity<T>(t: T) -> T {
+    t
+}
+
+fn opt_from_str<S: AsRef<str>>(a: S) -> Option<String> {
+    if a.as_ref().is_empty() {
+        None
+    } else {
+        Some(a.as_ref().to_owned())
+    }
+}
+
+fn is_ne<T: PartialEq>(t: &mut T, a: &T) -> bool {
+    t != a
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn render_true() {
+        let mut t = String::from("foo");
+        let should = render_if_ne(&mut t, String::from("bar"));
+        assert!(should, "Should have determined to render");
+        assert_eq!(t, String::from("bar"));
+    }
+
+    #[test]
+    fn render_false() {
+        let mut t = String::from("foo");
+        let should = render_if_ne(&mut t, String::from("foo"));
+        assert!(!should, "Should have determined to render");
+        assert_eq!(t, String::from("foo"));
+    }
+
+    #[test]
+    fn render_if_opt() {
+        let mut t = Some(String::from("test"));
+        let should = render_if_opt_str(&mut t, String::default());
+        assert!(should, "Should have determined to render");
+        assert_eq!(t, None);
+    }
+}