bit math only change

Author: aditi-khare-mongoDB

src/long.ts

@@ -243,20 +243,13 @@ export class Long extends BSONValue {
    * @returns The corresponding Long value
    */
   static fromBigInt(value: bigint, unsigned?: boolean): Long {
-    const byteStr = value.toString(16);
-    const isNeg = byteStr[0] === '-';
-    const startIndex = isNeg ? 1 : 0;
-    const lowByteString =
-      byteStr.length - startIndex > 8
-        ? byteStr.substring(byteStr.length - 8, byteStr.length)
-        : isNeg
-          ? byteStr.slice(1)
-          : byteStr;
-    const highByteString =
-      byteStr.length - startIndex > 8 ? byteStr.substring(startIndex, byteStr.length - 8) : 0;
-    return isNeg
-      ? new Long(Number('0x' + lowByteString), Number('0x' + highByteString), unsigned).neg()
-      : new Long(Number('0x' + lowByteString), Number('0x' + highByteString), unsigned);
+    /* eslint-disable no-bigint-usage/no-bigint-literals */
+    const bit32Mask = 0xffffffffn;
+
+    const lowBits = value & bit32Mask;
+    const highBits = (value >> 32n) & bit32Mask;
+    /* eslint-enable no-bigint-usage/no-bigint-literals */
+    return new Long(Number(lowBits), Number(highBits), unsigned);
   }
 
   /**