Fix: Reserve after deserialization in JS (#484)

I got an error when I loaded and searched with load() or view().

Code Example:

```js
// Saved with `index.save('index.usearch');` in another script.
index.load('index.usearch');
const results = index.search(new Float32Array([0.2, 0.6, 0.4]), 10);
```

javascript/lib.cpp

@@ -131,6 +131,8 @@ void CompiledIndex::Load(Napi::CallbackInfo const& ctx) {
         auto result = native_->load(path.c_str());
         if (!result)
             Napi::TypeError::New(ctx.Env(), result.error.release()).ThrowAsJavaScriptException();
+        if (!native_->try_reserve(ceil2(native_->size())))
+            Napi::Error::New(ctx.Env(), "Failed to reserve memory").ThrowAsJavaScriptException();
 
     } catch (...) {
         Napi::TypeError::New(ctx.Env(), "Loading failed").ThrowAsJavaScriptException();
@@ -144,6 +146,8 @@ void CompiledIndex::View(Napi::CallbackInfo const& ctx) {
         auto result = native_->view(path.c_str());
         if (!result)
             Napi::TypeError::New(ctx.Env(), result.error.release()).ThrowAsJavaScriptException();
+        if (!native_->try_reserve(ceil2(native_->size())))
+            Napi::Error::New(ctx.Env(), "Failed to reserve memory").ThrowAsJavaScriptException();
 
     } catch (...) {
         Napi::TypeError::New(ctx.Env(), "Memory-mapping failed").ThrowAsJavaScriptException();

javascript/usearch.test.js

@@ -1,5 +1,8 @@
 const test = require('node:test');
 const assert = require('node:assert');
+const fs = require('node:fs');
+const os = require('node:os');
+const path = require('node:path');
 const usearch = require('./dist/cjs/usearch.js');
 
 function assertAlmostEqual(actual, expected, tolerance = 1e-6) {
@@ -122,3 +125,50 @@ test('Invalid operations', async (t) => {
         );
     });
 });
+
+
+test('Serialization', async (t) => {
+    const indexPath = path.join(os.tmpdir(), 'usearch.test.index')
+
+    t.beforeEach(() => {
+        const index = new usearch.Index({
+            metric: "l2sq",
+            connectivity: 16,
+            dimensions: 3,
+        });
+        index.add(42n, new Float32Array([0.2, 0.6, 0.4]));
+        index.save(indexPath);
+    });
+
+    t.afterEach(() => {
+        fs.unlinkSync(indexPath);
+    });
+
+    await t.test('load', () => {
+        const index = new usearch.Index({
+            metric: "l2sq",
+            connectivity: 16,
+            dimensions: 3,
+        });
+        index.load(indexPath);
+        const results = index.search(new Float32Array([0.2, 0.6, 0.4]), 10);
+
+        assert.equal(index.size(), 1);
+        assert.deepEqual(results.keys, new BigUint64Array([42n]));
+        assertAlmostEqual(results.distances[0], new Float32Array([0]));
+    });
+
+    await t.test('view', () => {
+        const index = new usearch.Index({
+            metric: "l2sq",
+            connectivity: 16,
+            dimensions: 3,
+        });
+        index.view(indexPath);
+        const results = index.search(new Float32Array([0.2, 0.6, 0.4]), 10);
+
+        assert.equal(index.size(), 1);
+        assert.deepEqual(results.keys, new BigUint64Array([42n]));
+        assertAlmostEqual(results.distances[0], new Float32Array([0]));
+    });
+});