Add BrowserConsoleError context accessor

src/frontend.rs

@@ -79,6 +79,48 @@ pub enum BrowserConsoleError {
     UnsupportedTarget
 }
 
+impl BrowserConsoleError {
+    /// Returns the contextual message associated with the error, when
+    /// available.
+    ///
+    /// This is primarily useful for surfacing browser-provided diagnostics in
+    /// higher-level logs or telemetry.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # #[cfg(feature = "frontend")]
+    /// # {
+    /// use masterror::frontend::BrowserConsoleError;
+    ///
+    /// let err = BrowserConsoleError::ConsoleUnavailable {
+    ///     message: "console missing".to_owned()
+    /// };
+    /// assert_eq!(err.context(), Some("console missing"));
+    ///
+    /// let err = BrowserConsoleError::ConsoleMethodNotCallable;
+    /// assert_eq!(err.context(), None);
+    /// # }
+    /// ```
+    pub fn context(&self) -> Option<&str> {
+        match self {
+            Self::Serialization {
+                message
+            }
+            | Self::ConsoleUnavailable {
+                message
+            }
+            | Self::ConsoleErrorUnavailable {
+                message
+            }
+            | Self::ConsoleInvocation {
+                message
+            } => Some(message.as_str()),
+            Self::ConsoleMethodNotCallable | Self::UnsupportedTarget => None
+        }
+    }
+}
+
 /// Extensions for serializing errors to JavaScript and logging to the browser
 /// console.
 #[cfg_attr(docsrs, doc(cfg(feature = "frontend")))]
@@ -181,6 +223,25 @@ mod tests {
     use super::*;
     use crate::AppCode;
 
+    #[test]
+    fn context_returns_optional_message() {
+        let serialization = BrowserConsoleError::Serialization {
+            message: "encode failed".to_owned()
+        };
+        assert_eq!(serialization.context(), Some("encode failed"));
+
+        let invocation = BrowserConsoleError::ConsoleInvocation {
+            message: "js error".to_owned()
+        };
+        assert_eq!(invocation.context(), Some("js error"));
+
+        assert_eq!(
+            BrowserConsoleError::ConsoleMethodNotCallable.context(),
+            None
+        );
+        assert_eq!(BrowserConsoleError::UnsupportedTarget.context(), None);
+    }
+
     #[cfg(not(target_arch = "wasm32"))]
     mod native {
         use super::*;