feat: add simple performance tracker

app/src/lib/performance/PerformanceViewer.svelte

@@ -0,0 +1,17 @@
+<script lang="ts">
+  import type { PerformanceStore } from ".";
+
+  export let store: PerformanceStore;
+
+  function getPerformanceData() {
+    return Object.entries($store.total).sort((a, b) => b[1] - a[1]);
+  }
+</script>
+
+{#if $store.runs.length !== 0}
+  {#each getPerformanceData() as [key, value]}
+    <p>{key}: {Math.floor(value * 100) / 100}ms</p>
+  {/each}
+{:else}
+  <p>No runs available</p>
+{/if}

app/src/lib/performance/index.ts

@@ -0,0 +1,62 @@
+import { readable, type Readable } from "svelte/store";
+
+type PerformanceData = {
+  total: Record<string, number>;
+  runs: Record<string, number[]>[];
+}
+export interface PerformanceStore extends Readable<PerformanceData> {
+  startRun(): void;
+  stopRun(): void;
+  addPoint(name: string, value?: number): void;
+}
+
+export function createPerformanceStore(): PerformanceStore {
+
+  let data: PerformanceData = { total: {}, runs: [] };
+
+  let currentRun: Record<string, number[]> | undefined;
+
+  let set: (v: PerformanceData) => void;
+
+  const { subscribe } = readable<PerformanceData>({ total: {}, runs: [] }, (_set) => {
+    set = _set;
+  });
+
+  function startRun() {
+    currentRun = {};
+  }
+
+  function stopRun() {
+    if (currentRun) {
+      // Calculate total
+      Object.keys(currentRun).forEach((name) => {
+        if (!currentRun?.[name]?.length) return;
+        let runTotal = currentRun[name].reduce((a, b) => a + b, 0) / currentRun[name].length;
+        if (!data.total[name]) {
+          data.total[name] = runTotal;
+        } else {
+          data.total[name] = (data.total[name] + runTotal) / 2;
+        }
+      });
+
+      data.runs.push(currentRun);
+      currentRun = undefined;
+      set(data);
+    }
+  }
+
+  function addPoint(name: string, value: number) {
+    if (!currentRun) return;
+    currentRun[name] = currentRun[name] || [];
+    currentRun[name].push(value);
+  }
+
+  return {
+    subscribe,
+    startRun,
+    stopRun,
+    addPoint,
+  }
+}
+
+export { default as PerformanceViewer } from "./PerformanceViewer.svelte";