add stringifyObjects option

Readme.md

@@ -140,6 +140,8 @@ When establishing a connection, you can set the following options:
 * `database`: Name of the database to use for this connection (Optional).
 * `charset`: The charset for the connection. (Default: `'UTF8_GENERAL_CI'`)
 * `timezone`: The timezone used to store local dates. (Default: `'local'`)
+* `stringifyObjects`: Stringify objects instead of converting to values. See
+issue [#501](https://github.com/felixge/node-mysql/issues/501). (Default: `'false'`)
 * `insecureAuth`: Allow connecting to MySQL instances that ask for the old
   (insecure) authentication method. (Default: `false`)
 * `typeCast`: Determines if column values should be converted to native

lib/Connection.js

@@ -150,7 +150,7 @@ Connection.prototype.format = function(sql, values) {
   if (typeof this.config.queryFormat == "function") {
     return this.config.queryFormat.call(this, sql, values, this.config.timezone);
   }
-  return SqlString.format(sql, values, this.config.timezone);
+  return SqlString.format(sql, values, this.config.stringifyObjects, this.config.timezone);
 };
 
 Connection.prototype._handleNetworkError = function(err) {

lib/ConnectionConfig.js

@@ -18,6 +18,7 @@ function ConnectionConfig(options) {
   this.supportBigNumbers  = options.supportBigNumbers || false;
   this.bigNumberStrings   = options.bigNumberStrings || false;
   this.debug              = options.debug;
+  this.stringifyObjects   = options.stringifyObjects || false;
   this.timezone           = options.timezone || 'local';
   this.flags              = options.flags || '';
   this.queryFormat        = options.queryFormat;

lib/protocol/SqlString.js

@@ -58,7 +58,7 @@ SqlString.arrayToList = function(array, timeZone) {
   }).join(', ');
 };
 
-SqlString.format = function(sql, values, timeZone) {
+SqlString.format = function(sql, values, stringifyObjects, timeZone) {
   values = [].concat(values);
 
   return sql.replace(/\?\??/g, function(match) {
@@ -69,7 +69,7 @@ SqlString.format = function(sql, values, timeZone) {
     if (match == "??") {
       return SqlString.escapeId(values.shift());
     }
-    return SqlString.escape(values.shift(), false, timeZone);
+    return SqlString.escape(values.shift(), stringifyObjects, timeZone);
   });
 };
 

test/unit/protocol/test-SqlString.js

@@ -129,4 +129,17 @@ test('SqlString.format', {
     var sql = SqlString.format('? and ?', ['hello?', 'b']);
     assert.equal(sql, "'hello?' and 'b'");
   },
+
+  'objects is converted to values': function () {
+    var sql = SqlString.format('?', { 'hello': 'world' }, false)
+    assert.equal(sql, "`hello` = 'world'")
+  },
+
+  'objects is not converted to values': function () {
+    var sql = SqlString.format('?', { 'hello': 'world' }, true)
+    assert.equal(sql, "'[object Object]'")
+
+    var sql = SqlString.format('?', { toString: function () { return 'hello' } }, true)
+    assert.equal(sql, "'hello'")
+  }
 });