feat(NODE-7314): export byteUtils & add missing methods

Author: tadjik1

src/bson.ts

@@ -49,7 +49,8 @@ export {
   MaxKey,
   BSONRegExp,
   Decimal128,
-  NumberUtils
+  NumberUtils,
+  ByteUtils
 };
 export { BSONValue, bsonType, type BSONTypeTag } from './bson_value';
 export { BSONError, BSONVersionError, BSONRuntimeError, BSONOffsetError } from './error';

src/utils/byte_utils.ts

@@ -15,6 +15,10 @@ export type ByteUtils = {
   allocate: (size: number) => Uint8Array;
   /** Create empty space of size, use pooled memory when available */
   allocateUnsafe: (size: number) => Uint8Array;
+  /** Compare 2 Uint8Arrays lexicographically */
+  compare: (buffer1: Uint8Array, buffer2: Uint8Array) => -1 | 0 | 1;
+  /** Concatenating all the Uint8Arrays in new Uint8Array. */
+  concat: (list: Uint8Array[]) => Uint8Array;
   /** Check if two Uint8Arrays are deep equal */
   equals: (a: Uint8Array, b: Uint8Array) => boolean;
   /** Check if two Uint8Arrays are deep equal */

src/utils/node_byte_utils.ts

@@ -10,6 +10,7 @@ type NodeJsBuffer = ArrayBufferView &
     toString: (this: Uint8Array, encoding: NodeJsEncoding, start?: number, end?: number) => string;
     equals: (this: Uint8Array, other: Uint8Array) => boolean;
     swap32: (this: NodeJsBuffer) => NodeJsBuffer;
+    compare: (this: Uint8Array, other: Uint8Array) => -1 | 0 | 1;
   };
 type NodeJsBufferConstructor = Omit<Uint8ArrayConstructor, 'from'> & {
   alloc: (size: number) => NodeJsBuffer;
@@ -21,6 +22,7 @@ type NodeJsBufferConstructor = Omit<Uint8ArrayConstructor, 'from'> & {
   from(base64: string, encoding: NodeJsEncoding): NodeJsBuffer;
   byteLength(input: string, encoding: 'utf8'): number;
   isBuffer(value: unknown): value is NodeJsBuffer;
+  concat(list: Uint8Array[]): NodeJsBuffer;
 };
 
 // This can be nullish, but we gate the nodejs functions on being exported whether or not this exists
@@ -88,6 +90,14 @@ export const nodeJsByteUtils = {
     return Buffer.allocUnsafe(size);
   },
 
+  compare(a: Uint8Array, b: Uint8Array) {
+    return nodeJsByteUtils.toLocalBufferType(a).compare(b);
+  },
+
+  concat(list: Uint8Array[]): NodeJsBuffer {
+    return Buffer.concat(list);
+  },
+
   equals(a: Uint8Array, b: Uint8Array): boolean {
     return nodeJsByteUtils.toLocalBufferType(a).equals(b);
   },

src/utils/web_byte_utils.ts

@@ -114,6 +114,42 @@ export const webByteUtils = {
     return webByteUtils.allocate(size);
   },
 
+  compare(a: Uint8Array, b: Uint8Array): -1 | 0 | 1 {
+    if (a === b) return 0;
+
+    const len = Math.min(a.length, b.length);
+
+    for (let i = 0; i < len; i++) {
+      if (a[i] < b[i]) return -1;
+      if (a[i] > b[i]) return 1;
+    }
+
+    if (a.length < b.length) return -1;
+    if (a.length > b.length) return 1;
+
+    return 0;
+  },
+
+  concat(list: Uint8Array[]): Uint8Array {
+    if (list.length === 0) return webByteUtils.allocate(0);
+    if (list.length === 1) return list[0];
+
+    let totalLength = 0;
+    for (const arr of list) {
+      totalLength += arr.length;
+    }
+
+    const result = webByteUtils.allocate(totalLength);
+    let offset = 0;
+
+    for (const arr of list) {
+      result.set(arr, offset);
+      offset += arr.length;
+    }
+
+    return result;
+  },
+
   equals(a: Uint8Array, b: Uint8Array): boolean {
     if (a.byteLength !== b.byteLength) {
       return false;

test/node/exports.test.ts

@@ -39,7 +39,8 @@ const EXPECTED_EXPORTS = [
   'deserializeStream',
   'BSON',
   'bsonType',
-  'NumberUtils'
+  'NumberUtils',
+  'ByteUtils'
 ];
 
 const EXPECTED_EJSON_EXPORTS = ['parse', 'stringify', 'serialize', 'deserialize'];