diff --git a/src/main.ts b/src/main.ts
index c7d4569..395b62f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,5 +1,6 @@
 import "./style.css";
 import * as echarts from "echarts";
+import type { CallbackDataParams } from "echarts/types/dist/shared";
 
 document.addEventListener("DOMContentLoaded", () => {
   const chartContainer = document.getElementById("app");
@@ -22,22 +23,18 @@ document.addEventListener("DOMContentLoaded", () => {
       {
         data: [150, 230, 224, 218, 135, 147, 260],
         type: "line",
+        name: "Weekly Data", // Add a name so seriesName has a value
       },
     ],
 
-    // tooltip: {
-    //   formatter: (params) => {
-    //     return `${params.name}, ${params.seriesName}`; // BUG: `name` and `seriesName` are unavailable because of incorrect typing
-    //   },
-    // },
-
-    // Awkward workaround to access `name` and `seriesName` fields without a TypeScript error (this shouldn't ):
     tooltip: {
-      formatter: ((params: echarts.DefaultLabelFormatterCallbackParams) => {
-        return `${params.name}, ${params.seriesName}`;
-      }) as echarts.TooltipComponentFormatterCallback<echarts.TooltipComponentFormatterCallbackParams>,
+      trigger: "axis", // or "item"
+      formatter: (params) => {
+        const param = (Array.isArray(params) ? params[0] : params) as CallbackDataParams;
+        return `${param.name}, ${param.seriesName || 'Series'}`;
+      },
     },
   };
 
   chart.setOption(option);
-});
+});
\ No newline at end of file