fix(ext-json): deserialize doubles as Number in relaxed mode

This ensures we take relaxed/strict mode into account when
deserializing a double, similar to the integer checks above it.

NODE-1639

lib/extended_json.js

@@ -38,15 +38,17 @@ const keysToCodecs = {
 
 function deserializeValue(self, key, value, options) {
   if (typeof value === 'number') {
+    if (options.relaxed) {
+      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) {
-      let int32Range = value >= BSON_INT32_MIN && value <= BSON_INT32_MAX,
-        int64Range = value >= BSON_INT64_MIN && value <= BSON_INT64_MAX;
-
-      if (int32Range) return options.strict ? new Int32(value) : value;
-      if (int64Range) return options.strict ? new Long.fromNumber(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 new Long.fromNumber(value);
     }
+
     // If the number is a non-integer or out of integer range, should interpret as BSON Double.
     return new Double(value);
   }

test/node/extended_json_tests.js

@@ -247,4 +247,10 @@ describe('Extended JSON', function() {
     // timestamp
     expect(result.timestamp).to.be.an.instanceOf(BSON.Timestamp);
   });
+
+  it('should return a native number for a double in relaxed mode', function() {
+    const result = EJSON.deserialize({ test: 34.12 }, { relaxed: true });
+    expect(result.test).to.equal(34.12);
+    expect(result.test).to.be.a('number');
+  });
 });