Add a TryCatch err method helper

Signed-off-by: Francis Bouvier <francis@lightpanda.io>

Author: francisbouvier

src/engines/v8/v8.zig

@@ -466,6 +466,18 @@ pub const TryCatch = struct {
         return null;
     }
 
+    // a shorthand method to return either the entire stack message
+    // or just the exception message
+    // - in Debug mode return the stack if available
+    // - otherwhise return the exception if available
+    // the caller needs to deinit the string returned
+    pub fn err(self: TryCatch, alloc: std.mem.Allocator, env: Env) anyerror!?[]const u8 {
+        if (builtin.mode == .Debug) {
+            if (try self.stack(alloc, env)) |msg| return msg;
+        }
+        return try self.exception(alloc, env);
+    }
+
     pub fn deinit(self: *TryCatch) void {
         self.inner.deinit();
     }

src/interfaces.zig

@@ -145,6 +145,13 @@ pub fn TryCatch(comptime T: type, comptime env: type) void {
         env: env,
     ) anyerror!?[]const u8);
 
+    // err()
+    assertDecl(T, "err", fn (
+        self: T,
+        alloc: std.mem.Allocator,
+        env: env,
+    ) anyerror!?[]const u8);
+
     // stack()
     assertDecl(T, "stack", fn (
         self: T,