diff --git a/wlopm.c b/wlopm.c
index 5e171c0..8ef3164 100644
--- a/wlopm.c
+++ b/wlopm.c
@@ -201,6 +201,17 @@ static char *power_mode_to_string (enum zwlr_output_power_v1_mode mode)
 	return mode == ZWLR_OUTPUT_POWER_V1_MODE_ON ? "on" : "off";
 }
 
+static void print_json_error (const char *output_name, const char *msg)
+{
+	fprintf(stdout,
+			"%s\n    {\n"
+			"      \"output\": \"%s\",\n"
+			"      \"error\": \"%s\"\n"
+			"    }",
+			json_prev ? "," : "", output_name, msg);
+	json_prev = true;
+}
+
 static void do_operation (struct Operation *operation)
 {
 	if ( *operation->name == '*' )
@@ -215,16 +226,7 @@ static void do_operation (struct Operation *operation)
 		if ( output == NULL )
 		{
 			if (json)
-			{
-				fprintf(stdout,
-						"%s\n    {\n"
-						"      \"output\": \"%s\",\n"
-						"      \"error\": \"output does not exist\"\n"
-						"    }",
-						json_prev ? "," : "",
-						operation->name);
-				json_prev = true;
-			}
+				print_json_error(operation->name, "output does not exist");
 			else
 				fprintf(stderr, "ERROR: Output '%s' does not exist.\n",
 						operation->name);
@@ -338,16 +340,7 @@ static void sync_handle_done (void *data, struct wl_callback *wl_callback, uint3
 			if (output->operation_failed)
 			{
 				if (json)
-				{
-					fprintf(stdout,
-							"%s\n    {\n"
-							"      \"output\": \"%s\","
-							"      \"error\": \"setting power mode failed\"\n"
-							"    }",
-							json_prev ? "," : "",
-							output->name);
-					json_prev = true;
-				}
+					print_json_error(output->name, "setting power mode failed");
 				else
 					fprintf(stderr, "ERROR: Setting power mode for output '%s' failed.\n",
 							output->name);