Reduce production bundles while preserving host registration

src/apps/readVersion.unit.spec.ts

@@ -0,0 +1,36 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { readVersion } from "./readVersion";
+
+describe("readVersion", () => {
+    let directory: string;
+
+    beforeEach(() => {
+        directory = mkdtempSync(join(tmpdir(), "livesync-read-version-"));
+    });
+
+    afterEach(() => {
+        rmSync(directory, { recursive: true, force: true });
+    });
+
+    it("returns only string version values", () => {
+        const filePath = join(directory, "version.json");
+        writeFileSync(filePath, JSON.stringify({ version: "1.2.3" }));
+        expect(readVersion(filePath)).toBe("1.2.3");
+
+        for (const contents of ["null", "[]", "{}", '{"version": 42}', '{"version": null}']) {
+            writeFileSync(filePath, contents);
+            expect(readVersion(filePath)).toBeUndefined();
+        }
+    });
+
+    it("preserves file read and JSON parse errors", () => {
+        expect(() => readVersion(join(directory, "missing.json"))).toThrow();
+
+        const filePath = join(directory, "invalid.json");
+        writeFileSync(filePath, "not JSON");
+        expect(() => readVersion(filePath)).toThrow(SyntaxError);
+    });
+});