Merge pull request #199 from farabi-deriv/farabi/bot-1887/trackjs-can…

…not-read-properties-of-null-connection

Farabi/bot-1887/trackjs-cannot-read-properties-of-null-connection

src/external/bot-skeleton/scratch/blocks/Binary/Trade Definition/trade_definition_market.js

@@ -116,7 +116,9 @@ window.Blockly.Blocks.trade_definition_market = {
                 // Reconnect self to trade definition block.
                 if (trade_definition_block) {
                     const connection = trade_definition_block.getLastConnectionInStatement('TRADE_OPTIONS');
-                    connection.connect(this.previousConnection);
+                    if (connection) {
+                        connection.connect(this.previousConnection);
+                    }
                 } else {
                     this.dispose();
                 }