fix: BigInt(Infinity) crash in readers + HNSW serialize round-trip

csv-reader/json-reader: BigInt(Math.trunc(Number(raw))) throws
RangeError when raw parses to Infinity/NaN (e.g. "1e999"). Now
guards with Number.isFinite() and returns null.

json-reader: Boolean(null) silently converted null to false in bool
columns, losing null semantics. Now returns null for null/undefined.

hnsw.ts: serialize() didn't write efConstruction, so deserialize()
always used default 200. Now included in header (29 bytes). Also
removed dead Float32Array allocation in serialize().

Author: teamchong

src/hnsw.ts

@@ -481,14 +481,15 @@ export class HnswIndex {
    * Serialize the index to a compact binary format.
    *
    * Layout:
-   *   Header (25 bytes):
+   *   Header (29 bytes):
    *     magic: u32 ("HNSW")
    *     dim: u32
    *     M: u32
    *     maxLevel: u32
    *     entryPoint: u32
    *     size: u32
    *     metric: u8
+   *     efConstruction: u32
    *   Vectors: size * dim * 4 bytes (float32)
    *   Node levels: size * u32
    *   Per level (maxLevel + 1 levels):
@@ -500,7 +501,7 @@ export class HnswIndex {
    */
   serialize(): ArrayBuffer {
     // Calculate total size
-    let totalSize = 25; // header
+    let totalSize = 29; // header
     totalSize += this._size * this.dim * 4; // vectors
     totalSize += this._size * 4; // node levels
 
@@ -515,7 +516,6 @@ export class HnswIndex {
 
     const buf = new ArrayBuffer(totalSize);
     const view = new DataView(buf);
-    const f32 = new Float32Array(buf);
     let offset = 0;
 
     // Header
@@ -526,6 +526,7 @@ export class HnswIndex {
     view.setUint32(offset, this.entryPoint >= 0 ? this.entryPoint : 0, true); offset += 4;
     view.setUint32(offset, this._size, true); offset += 4;
     view.setUint8(offset, METRIC_BYTE[this.metric] ?? 0); offset += 1;
+    view.setUint32(offset, this.efConstruction, true); offset += 4;
 
     // Vectors
     for (let i = 0; i < this._size; i++) {
@@ -576,10 +577,12 @@ export class HnswIndex {
     const entryPoint = view.getUint32(offset, true); offset += 4;
     const size = view.getUint32(offset, true); offset += 4;
     const metricByte = view.getUint8(offset); offset += 1;
+    const efConstruction = offset + 4 <= data.byteLength ? view.getUint32(offset, true) : 200;
+    offset += 4;
 
     const resolvedMetric = metric ?? BYTE_METRIC[metricByte] ?? "cosine";
 
-    const idx = new HnswIndex({ dim, metric: resolvedMetric, M });
+    const idx = new HnswIndex({ dim, metric: resolvedMetric, M, efConstruction });
     idx.maxLevel = size > 0 ? maxLevel : -1;
     idx.entryPoint = size > 0 ? entryPoint : -1;
 

src/readers/csv-reader.ts

@@ -170,8 +170,11 @@ function coerceValue(raw: string, dtype: DataType): number | bigint | string | b
       const lower = trimmed.toLowerCase();
       return lower === "true" || lower === "1";
     }
-    case "int64":
-      return BigInt(Math.trunc(Number(trimmed)));
+    case "int64": {
+      const n = Number(trimmed);
+      if (!Number.isFinite(n)) return null;
+      return BigInt(Math.trunc(n));
+    }
     case "float64":
       return Number(trimmed);
     default:

src/readers/json-reader.ts

@@ -49,10 +49,14 @@ function coerceValue(raw: unknown, dtype: DataType): number | bigint | string |
   if (raw === null || raw === undefined) return null;
   switch (dtype) {
     case "bool":
+      if (raw === null || raw === undefined) return null;
       return Boolean(raw);
-    case "int64":
+    case "int64": {
       if (typeof raw === "bigint") return raw;
-      return BigInt(Math.trunc(Number(raw)));
+      const n = Number(raw);
+      if (!Number.isFinite(n)) return null;
+      return BigInt(Math.trunc(n));
+    }
     case "float64":
       return Number(raw);
     case "utf8":
@@ -66,9 +70,12 @@ function coerceValue(raw: unknown, dtype: DataType): number | bigint | string |
     case "uint32":
     case "float32":
       return Number(raw);
-    case "uint64":
+    case "uint64": {
       if (typeof raw === "bigint") return raw;
-      return BigInt(Math.trunc(Number(raw)));
+      const n = Number(raw);
+      if (!Number.isFinite(n)) return null;
+      return BigInt(Math.trunc(n));
+    }
     default:
       return String(raw);
   }