fix(NODE-4464):stringify and parse negative zero to and from $numberD…

…ouble: -0.0 (#531)

src/extended_json.ts

@@ -73,11 +73,15 @@ function deserializeValue(value: any, options: EJSON.Options = {}) {
       return value;
     }
 
-    // if it's an integer, should interpret as smallest BSON integer
-    // that can represent it exactly. (if out of range, interpret as double.)
-    if (Math.floor(value) === value) {
-      if (value >= BSON_INT32_MIN && value <= BSON_INT32_MAX) return new Int32(value);
-      if (value >= BSON_INT64_MIN && value <= BSON_INT64_MAX) return Long.fromNumber(value);
+    if (Number.isInteger(value) && !Object.is(value, -0)) {
+      // interpret as being of the smallest BSON integer type that can represent the number exactly
+      if (value >= BSON_INT32_MIN && value <= BSON_INT32_MAX) {
+        return new Int32(value);
+      }
+      if (value >= BSON_INT64_MIN && value <= BSON_INT64_MAX) {
+        // TODO(NODE-4377): EJSON js number handling diverges from BSON
+        return Long.fromNumber(value);
+      }
     }
 
     // If the number is a non-integer or out of integer range, should interpret as BSON Double.
@@ -216,16 +220,17 @@ function serializeValue(value: any, options: EJSONSerializeOptions): any {
   }
 
   if (typeof value === 'number' && (!options.relaxed || !isFinite(value))) {
-    // it's an integer
-    if (Math.floor(value) === value) {
-      const int32Range = value >= BSON_INT32_MIN && value <= BSON_INT32_MAX,
-        int64Range = value >= BSON_INT64_MIN && value <= BSON_INT64_MAX;
-
+    if (Number.isInteger(value) && !Object.is(value, -0)) {
       // interpret as being of the smallest BSON integer type that can represent the number exactly
-      if (int32Range) return { $numberInt: value.toString() };
-      if (int64Range) return { $numberLong: value.toString() };
+      if (value >= BSON_INT32_MIN && value <= BSON_INT32_MAX) {
+        return { $numberInt: value.toString() };
+      }
+      if (value >= BSON_INT64_MIN && value <= BSON_INT64_MAX) {
+        // TODO(NODE-4377): EJSON js number handling diverges from BSON
+        return { $numberLong: value.toString() };
+      }
     }
-    return { $numberDouble: value.toString() };
+    return { $numberDouble: Object.is(value, -0) ? '-0.0' : value.toString() };
   }
 
   if (value instanceof RegExp || isRegExp(value)) {

test/node/bson_corpus.spec.test.js

@@ -47,6 +47,8 @@ function nativeToREJSON(native) {
 }
 
 function normalize(cEJ) {
+  // TODO(NODE-3396): loses information about the original input
+  // ex. parse will preserve -0 but stringify will output +0
   return JSON.stringify(JSON.parse(cEJ));
 }
 

test/node/double_tests.js → test/node/double.test.ts

@@ -1,6 +1,4 @@
-'use strict';
-
-const BSON = require('../register-bson');
+import * as BSON from '../register-bson';
 const Double = BSON.Double;
 
 describe('BSON Double Precision', function () {
@@ -89,4 +87,30 @@ describe('BSON Double Precision', function () {
     expect(type).to.not.equal(BSON.BSON_DATA_NUMBER);
     expect(type).to.equal(BSON.BSON_DATA_INT);
   });
+
+  describe('extended JSON', () => {
+    describe('stringify()', () => {
+      it('preserves negative zero in canonical format', () => {
+        const result = BSON.EJSON.stringify({ a: -0.0 }, { relaxed: false });
+        expect(result).to.equal(`{"a":{"$numberDouble":"-0.0"}}`);
+      });
+
+      it('loses negative zero in relaxed format', () => {
+        const result = BSON.EJSON.stringify({ a: -0.0 }, { relaxed: true });
+        expect(result).to.equal(`{"a":0}`);
+      });
+    });
+
+    describe('parse()', () => {
+      it('preserves negative zero in deserialization with relaxed false', () => {
+        const result = BSON.EJSON.parse(`{ "a": -0.0 }`, { relaxed: false });
+        expect(result.a).to.have.property('_bsontype', 'Double');
+      });
+
+      it('preserves negative zero in deserialization with relaxed true', () => {
+        const result = BSON.EJSON.parse(`{ "a": -0.0 }`, { relaxed: true });
+        expect(Object.is(result.a, -0), 'expected prop a to be negative zero').to.be.true;
+      });
+    });
+  });
 });

test/node/extended_json_tests.js

@@ -79,7 +79,7 @@ describe('Extended JSON', function () {
   });
 
   it('should correctly extend an existing mongodb module', function () {
-    // Serialize the document
+    // TODO(NODE-4377): doubleNumberIntFit should be a double not a $numberLong
     var json =
       '{"_id":{"$numberInt":"100"},"gh":{"$numberInt":"1"},"binary":{"$binary":{"base64":"AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4vMDEyMzQ1Njc4OTo7PD0+Pw==","subType":"00"}},"date":{"$date":{"$numberLong":"1488372056737"}},"code":{"$code":"function() {}","$scope":{"a":{"$numberInt":"1"}}},"dbRef":{"$ref":"tests","$id":{"$numberInt":"1"},"$db":"test"},"decimal":{"$numberDecimal":"100"},"double":{"$numberDouble":"10.1"},"int32":{"$numberInt":"10"},"long":{"$numberLong":"200"},"maxKey":{"$maxKey":1},"minKey":{"$minKey":1},"objectId":{"$oid":"111111111111111111111111"},"objectID":{"$oid":"111111111111111111111111"},"oldObjectID":{"$oid":"111111111111111111111111"},"regexp":{"$regularExpression":{"pattern":"hello world","options":"i"}},"symbol":{"$symbol":"symbol"},"timestamp":{"$timestamp":{"t":0,"i":1000}},"int32Number":{"$numberInt":"300"},"doubleNumber":{"$numberDouble":"200.2"},"longNumberIntFit":{"$numberLong":"7036874417766400"},"doubleNumberIntFit":{"$numberLong":"19007199250000000"}}';
 
@@ -103,6 +103,7 @@ describe('Extended JSON', function () {
     expect(doc1.int32Number._bsontype).to.equal('Int32');
     expect(doc1.doubleNumber._bsontype).to.equal('Double');
     expect(doc1.longNumberIntFit._bsontype).to.equal('Long');
+    // TODO(NODE-4377): EJSON should not try to make Longs from large ints
     expect(doc1.doubleNumberIntFit._bsontype).to.equal('Long');
   });