Sample nightwatch.js assertion in multiple items

google.js

module.exports = {
    url: 'http://google.com',
    elements: {
      searchBar: { 
        selector: 'input[type=text]' 
      },
      btn: { 
        selector: 'input[type=submit]', 
      }
    },
    commands: [
        {
            assertBtnText: function(index, text){
                var i = index + 1
                return this.getValue(`input[type=submit]:nth-child(${i})`, function(result){
                    this.assert.equal(result.value, text)
                });
            }
        }
    ]
  };

googleTest.js

module.exports = {
    'Test': function (client) {
      var google = client.page.google();
  
      google.navigate()
        .assert.title('Google')
        .assert.visible('@searchBar')
        .setValue('@searchBar', 'nightwatch');
  
        google.assertBtnText(0,"Pesquisa Google")
        google.assertBtnText(1,"Sinto-me com sorte")

      client.end();
    }
  };