Add base fee to the chart

src/special/london/chart.ts

@@ -28,6 +28,17 @@ export const options: ChartOptions = {
         callback: (v) => `${v} Gwei`,
       },
     },
+    yBaseFee: {
+      position: "right",
+      beginAtZero: true,
+      title: {
+        display: true,
+        text: "Base fee",
+      },
+      grid: {
+        drawOnChartArea: false
+      }
+    },
   },
 };
 
@@ -44,5 +55,12 @@ export const toChartData = (blocks: ExtendedBlock[]): ChartData => ({
       borderColor: "#F97316",
       tension: 0.2,
     },
+    {
+      label: "Base fee (Gwei)",
+      data: blocks.map(b => b.baseFeePerGas!.toNumber()).reverse(),
+      yAxisID: "yBaseFee",
+      borderColor: "#FCA5A5",
+      tension: 0.2
+    }
   ],
 });