feat: add vitest pkg, formatBytes lib function with tests

frontend/package.json

@@ -23,6 +23,7 @@
     "@types/react-dom": "^18.0.6",
     "@vitejs/plugin-react": "^2.0.1",
     "typescript": "^4.6.4",
-    "vite": "^3.0.7"
+    "vite": "^3.0.7",
+    "vitest": "^3.2.4"
   }
 }

frontend/package.json.md5

@@ -1 +1 @@
-09087dfd9742bacd550951060ae8f28f
+435a9196aacc1e4aa5eb43cd8621ad0e

frontend/pnpm-workspace.yaml

@@ -0,0 +1,2 @@
+onlyBuiltDependencies:
+  - esbuild

frontend/src/lib/format.test.ts

@@ -0,0 +1,28 @@
+import { formatBytes } from "./format.js";
+import { test, expect } from "vitest";
+
+test("formats bytes less than 1024", () => {
+  expect(formatBytes(512)).toBe("512 B");
+});
+
+test("formats KiB correctly", () => {
+  expect(formatBytes(2048)).toBe("2 KiB");
+  expect(formatBytes(1536)).toBe("1.5 KiB");
+  expect(formatBytes(1024)).toBe("1 KiB");
+});
+
+test("formats MiB correctly", () => {
+  expect(formatBytes(1048576)).toBe("1 MiB");
+  expect(formatBytes(1572864)).toBe("1.5 MiB");
+  expect(formatBytes(2097152)).toBe("2 MiB");
+});
+
+test("formats GiB correctly", () => {
+  expect(formatBytes(1073741824)).toBe("1 GiB");
+  expect(formatBytes(1610612736)).toBe("1.5 GiB");
+  expect(formatBytes(2147483648)).toBe("2 GiB");
+});
+
+test("formats large values with no decimal if intValue >= 1000", () => {
+  expect(formatBytes(1024 * 1024 * 1000)).toBe("1000 MiB");
+});

frontend/src/lib/format.ts

@@ -0,0 +1,38 @@
+/**
+ * Formats a number of bytes into a human-readable string using binary units (KiB, MiB, GiB, TiB).
+ *
+ * - For values less than 1024, returns the value in bytes (e.g., "512 B").
+ * - For larger values, converts to the appropriate unit and formats:
+ *   - If the integer part is 1000 or more, shows no decimal (e.g., "1024 KiB").
+ *   - If the decimal part is at least 0.1, shows one decimal place (e.g., 1228.8 KiB formats as "1.2 MiB").
+ *   - Otherwise, shows no decimal (e.g., 1075.2 MiB == 1.05 GiB, formats as "1 GiB").
+ *
+ * @param v - The number of bytes to format.
+ * @returns The formatted string with the appropriate unit.
+ */
+export function formatBytes(v: number): string {
+  if (v < 1024) return `${v} B`;
+
+  const units = ["KiB", "MiB", "GiB", "TiB"];
+  let unitIndex = -1;
+  let value = v;
+
+  while (value >= 1024 && unitIndex < units.length - 1) {
+    value /= 1024;
+    unitIndex++;
+  }
+
+  const intValue = Math.floor(value);
+  const decimal = value - intValue;
+
+  if (intValue >= 1000) {
+    // More than 3 digits, no decimal
+    return `${intValue} ${units[unitIndex]}`;
+  } else if (decimal >= 0.1) {
+    // Show 1 decimal if decimal >= 0.1
+    return `${value.toFixed(1)} ${units[unitIndex]}`;
+  } else {
+    // No decimal
+    return `${intValue} ${units[unitIndex]}`;
+  }
+}