Stuck on an issue?

This error appears when I run like this: testmybot-master/samples/watson$ npm run emulatorBrowser

readConvos error: TypeError: Converting circular structure to JSON

I found which place throws error:

/samples/watson/node_modules/testmybot/src/emulator/browser/index.js

  router.route('/testcases')
    .post(function(req, res) {
      if (!req.body.header || !req.body.header.name)
        return res.json({ success: false, error: 'Name not specified' });
      if (!req.body.conversation)
        return res.json({ success: false, error: 'Conversation not specified' });

      try {
        const filename = tmb.convoReader.writeConvo(req.body, true);
        return res.json({ success: true, filename: filename });
      } catch (err) {
        console.log('writeConvo error: ' + err);
        return res.json({ success: false, error: err });
      }
    }).get(function(req, res) {
      try {
        const convos = tmb.convoReader.readConvos()
        return res.json(convos);  // <---- This line says "TypeError: Converting circular structure to JSON"
      } catch (err) {        
        console.log('readConvos error: ' + err);
        return res.json({ success: false, error: err });
      }
    });

I’ve logged convos value before throwing error, this is convos’s value:

[ Convo {
    provider: 
     ScriptingProvider {
       caps: [Object],
       compilers: [Object],
       convos: [Circular],
       utterances: {},
       match: [Function],
       scriptingEvents: [Object] },
    header: ConvoHeader { name: 'testt_1', order: 1, description: undefined },
    conversation: [ [Object], [Object], [Object], [Object] ],
    sourceTag: 'testt_1.convo.txt' },
  Convo {
    provider: 
     ScriptingProvider {
       caps: [Object],
       compilers: [Object],
       convos: [Circular],
       utterances: {},
       match: [Function],
       scriptingEvents: [Object] },
    header: ConvoHeader { name: 'testt_2', order: 2, description: undefined },
    conversation: 
     [ [Object],
       [Object],
       [Object],
       [Object],
       [Object],
       [Object],
       [Object] ],
    sourceTag: 'testt_2.convo.txt' } ]

>npm run emulator works fine, only >npm run emulatorBrowser throws above error. Browser opens http://127.0.0.1:3000/#!/testsuite but there is nothing to do there, busy loader rotates. I’m using nodejs v6.9.5, npm 3.10.10, kubuntu 16.04