Use new toString for toJson

Author: tcannon91

snippets/mongocompat/mongotypes.js

@@ -443,15 +443,15 @@ if (typeof NumberDecimal !== 'undefined') {
     if (!NumberDecimal.prototype) {
         NumberDecimal.prototype = {};
     }
-    NumberDecimal.prototype.nativeToString = NumberDecimal.prototype.toString
-
-    NumberDecimal.prototype.tojson = function() {
-        return this.nativeToString();
-    };
 
+    NumberDecimal.prototype.nativeToString = NumberDecimal.prototype.toString
     NumberDecimal.prototype.toString = function() {
         return `NumberDecimal("${this.nativeToString()}")`;
     };
+
+    NumberDecimal.prototype.tojson = function() {
+        return this.toString();
+    };
 }
 
 // ObjectId

snippets/mongocompat/test.js

@@ -24,4 +24,4 @@ const nl2 = NumberLong("200");
 assert.strictEqual(maxLong.compare(nl2), 1);
 const decimal = NumberDecimal("1.1");
 assert.strictEqual(decimal.toString(), 'NumberDecimal("1.1")');
-assert.strictEqual(decimal.tojson(), '1.1');
+assert.strictEqual(decimal.tojson(), 'NumberDecimal("1.1")');