conditional validation

src/controls/button.rs

@@ -44,7 +44,7 @@ impl<FD: FormToolData> FormBuilder<FD> {
         let cx = self.cx.clone();
         let render_fn = move |fs: Rc<FD::Style>, fd: RwSignal<FD>| {
             let render_data = Rc::new(render_data);
-            // let cloned_fs = fs.clone();
+
             let view = move || fs.clone().button(render_data.clone(), fd);
             let view = match show_when {
                 Some(when) => {

src/controls/mod.rs

@@ -19,7 +19,7 @@ pub mod text_area;
 pub mod text_input;
 
 pub trait BuilderFn<B, CX>: Fn(B, Rc<CX>) -> B {}
-pub trait ValidationFn<FDT: ?Sized>: Fn(&FDT) -> Result<(), String> + 'static {}
+pub trait ValidationFn<FD: ?Sized>: Fn(&FD) -> Result<(), String> + 'static {}
 pub trait ValidationCb: Fn() -> bool + 'static {}
 pub trait ParseFn<CR, FDT>: Fn(CR) -> Result<FDT, String> + 'static {}
 pub trait UnparseFn<CR, FDT>: Fn(FDT) -> CR + 'static {}
@@ -177,7 +177,7 @@ pub(crate) struct BuiltControlData<FD: FormToolData, C: ControlData, FDT> {
     pub(crate) parse_fn: Box<dyn ParseFn<C::ReturnType, FDT>>,
     pub(crate) unparse_fn: Box<dyn UnparseFn<C::ReturnType, FDT>>,
     pub(crate) validation_fn: Option<Rc<dyn ValidationFn<FD>>>,
-    pub(crate) show_when: Option<Box<dyn ShowWhenFn<FD, FD::Context>>>,
+    pub(crate) show_when: Option<Rc<dyn ShowWhenFn<FD, FD::Context>>>,
 }
 
 /// A builder for a interactive control.
@@ -188,7 +188,7 @@ pub struct ControlBuilder<FD: FormToolData, C: ControlData, FDT> {
     pub(crate) unparse_fn: Option<Box<dyn UnparseFn<C::ReturnType, FDT>>>,
     pub(crate) validation_fn: Option<Rc<dyn ValidationFn<FD>>>,
     pub(crate) style_attributes: Vec<<FD::Style as FormStyle>::StylingAttributes>,
-    pub(crate) show_when: Option<Box<dyn ShowWhenFn<FD, FD::Context>>>,
+    pub(crate) show_when: Option<Rc<dyn ShowWhenFn<FD, FD::Context>>>,
     pub data: C,
 }
 
@@ -249,7 +249,7 @@ impl<FD: FormToolData, C: ControlData, FDT> ControlBuilder<FD, C, FDT> {
         mut self,
         when: impl Fn(Signal<FD>, Rc<FD::Context>) -> bool + 'static,
     ) -> Self {
-        self.show_when = Some(Box::new(when));
+        self.show_when = Some(Rc::new(when));
         self
     }
 

src/form.rs

@@ -33,7 +33,9 @@ impl<FD: FormToolData> FormValidator<FD> {
 /// With this, you can render the form, get the form data, or get
 /// a validator for the data.
 pub struct Form<FD: FormToolData> {
+    /// The form data signal.
     pub fd: RwSignal<FD>,
+    /// The list of validations
     pub(crate) validations: Vec<Rc<dyn ValidationFn<FD>>>,
     pub(crate) view: View,
 }

src/form_builder.rs

@@ -125,8 +125,24 @@ impl<FD: FormToolData> FormBuilder<FD> {
             Err(e) => panic!("Invalid Component: {}", e),
         };
 
-        if let Some(ref validation_fn) = built_control_data.validation_fn {
-            self.validations.push(validation_fn.clone());
+        if let Some(validation_fn) = built_control_data.validation_fn.clone() {
+            let validation_fn = if let Some(show_when) = built_control_data.show_when.clone() {
+                // we want the validation function to always succeed for hidden components
+                // thus, we need to modify the validation function
+                let cx = self.cx.clone();
+                let new_validation_fn = move |fd: &FD| {
+                    let (fd_signal, _) = create_signal(fd.clone());
+                    if !show_when(fd_signal.into(), cx.clone()) {
+                        return Ok(());
+                    }
+                    validation_fn(fd)
+                };
+                Rc::new(new_validation_fn)
+            } else {
+                validation_fn
+            };
+
+            self.validations.push(validation_fn);
         }
 
         let cx = self.cx.clone();
@@ -174,14 +190,29 @@ impl<FD: FormToolData> FormBuilder<FD> {
         };
         let value_getter = value_getter.into_signal();
 
+        let cloned_show_when = show_when.clone();
+        let cloned_cx = cx.clone();
         let validation_cb = move || {
-            let validation_fn = validation_fn.as_ref();
+            // first check if the validation signal is an error so that we
+            // can fail on parsing issues too
+            if let Some(Err(_)) = validation_signal.try_get_untracked() {
+                return false;
+            }
+
+            // validation for non-visible fields always succeeds
+            if let Some(ref show_when) = cloned_show_when {
+                if !show_when(fd.into(), cloned_cx.clone()) {
+                    return true;
+                }
+            }
+
+            // run the validation function on the value now
             let validation_fn = match validation_fn {
-                Some(v) => v,
-                None => return true, // No validation function, so validation passes
+                Some(ref v) => v,
+                None => return true, // No validation function so validation passes
             };
 
-            let data = fd.get();
+            let data = fd.get_untracked();
             let validation_result = validation_fn(&data);
             let succeeded = validation_result.is_ok();
             validation_signal_set.set(validation_result);