:recycle: Refactor event handlers as proper decoders.

4 files changed, 12 insertions, 17 deletions

diff --git a/src/lustre/event.gleam b/src/lustre/event.gleam
index 2250057..e8c8b0d 100644
--- a/src/lustre/event.gleam
+++ b/src/lustre/event.gleam
@@ -6,7 +6,7 @@
 
 // IMPORTS ---------------------------------------------------------------------
 
-import gleam/dynamic.{type DecodeError, type Dynamic}
+import gleam/dynamic.{type DecodeError, type Decoder, type Dynamic}
 import gleam/json.{type Json}
 import gleam/result
 import lustre/attribute.{type Attribute}
@@ -39,10 +39,7 @@ pub fn emit(event: String, data: Json) -> Effect(msg) {
 /// If you're listening for non-standard events (like those emitted by a custom
 /// element) their event names might be slightly different.
 ///
-pub fn on(
-  name: String,
-  handler: fn(Dynamic) -> Result(msg, error),
-) -> Attribute(msg) {
+pub fn on(name: String, handler: Decoder(msg)) -> Attribute(msg) {
   attribute.on(name, handler)
 }
 
diff --git a/src/lustre/internals/patch.gleam b/src/lustre/internals/patch.gleam
index a0fff47..b93a9a6 100644
--- a/src/lustre/internals/patch.gleam
+++ b/src/lustre/internals/patch.gleam
@@ -2,7 +2,7 @@
 
 import gleam/bool
 import gleam/dict.{type Dict}
-import gleam/dynamic.{type Dynamic}
+import gleam/dynamic.{type Decoder}
 import gleam/int
 import gleam/json.{type Json}
 import gleam/list
@@ -27,7 +27,7 @@ pub type ElementDiff(msg) {
     created: Dict(String, Element(msg)),
     removed: Set(String),
     updated: Dict(String, AttributeDiff(msg)),
-    handlers: Dict(String, fn(Dynamic) -> Result(msg, Nil)),
+    handlers: Dict(String, Decoder(msg)),
   )
 }
 
@@ -35,7 +35,7 @@ pub type AttributeDiff(msg) {
   AttributeDiff(
     created: Set(Attribute(msg)),
     removed: Set(String),
-    handlers: Dict(String, fn(Dynamic) -> Result(msg, Nil)),
+    handlers: Dict(String, Decoder(msg)),
   )
 }
 
@@ -330,7 +330,7 @@ fn attribute_dict(
 
 fn event_handler(
   attribute: Attribute(msg),
-) -> Result(#(String, fn(Dynamic) -> Result(msg, Nil)), Nil) {
+) -> Result(#(String, Decoder(msg)), Nil) {
   case attribute {
     Attribute(_, _, _) -> Error(Nil)
     Event(name, handler) -> {
@@ -342,10 +342,10 @@ fn event_handler(
 }
 
 fn fold_event_handlers(
-  handlers: Dict(String, fn(Dynamic) -> Result(msg, Nil)),
+  handlers: Dict(String, Decoder(msg)),
   element: Element(msg),
   key: String,
-) -> Dict(String, fn(Dynamic) -> Result(msg, Nil)) {
+) -> Dict(String, Decoder(msg)) {
   case element {
     Text(_) -> handlers
     Map(subtree) -> fold_event_handlers(handlers, subtree(), key)
diff --git a/src/lustre/internals/runtime.gleam b/src/lustre/internals/runtime.gleam
index f9c4e87..a2b5365 100644
--- a/src/lustre/internals/runtime.gleam
+++ b/src/lustre/internals/runtime.gleam
@@ -25,7 +25,7 @@ type State(model, msg, runtime) {
     view: fn(model) -> Element(msg),
     html: Element(msg),
     renderers: Dict(String, fn(Patch(msg)) -> Nil),
-    handlers: Dict(String, fn(Dynamic) -> Result(msg, Nil)),
+    handlers: Dict(String, Decoder(msg)),
     on_attribute_change: Dict(String, Decoder(msg)),
   )
 }
diff --git a/src/lustre/internals/vdom.gleam b/src/lustre/internals/vdom.gleam
index 1bbf9fc..c803b44 100644
--- a/src/lustre/internals/vdom.gleam
+++ b/src/lustre/internals/vdom.gleam
@@ -32,17 +32,15 @@ pub type Attribute(msg) {
 
 // QUERIES ---------------------------------------------------------------------
 
-pub fn handlers(
-  element: Element(msg),
-) -> Dict(String, fn(Dynamic) -> Result(msg, Nil)) {
+pub fn handlers(element: Element(msg)) -> Dict(String, Decoder(msg)) {
   do_handlers(element, dict.new(), "0")
 }
 
 fn do_handlers(
   element: Element(msg),
-  handlers: Dict(String, fn(Dynamic) -> Result(msg, Nil)),
+  handlers: Dict(String, Decoder(msg)),
   key: String,
-) -> Dict(String, fn(Dynamic) -> Result(msg, Nil)) {
+) -> Dict(String, Decoder(msg)) {
   case element {
     Text(_) -> handlers
     Map(subtree) -> do_handlers(subtree(), handlers, key)