Rating (type:'rating')

Source code: Survey setup
Survey.defaultBootstrapCss.navigationButton = "btn btn-primary";
Survey.Survey.cssType = "bootstrap";
var survey = new Survey.Model({questions:[    
    { type: "rating", name: "satisfaction", title: "How satisfied are you with the Product?", 
        mininumRateDescription: "Not Satisfied", maximumRateDescription: "Completely satisfied" }]
});

var app = new Vue({
    el: '#surveyElement',
    data: {
        survey: survey
    }
});

Minimum Rate Description: (default is empty)

var q = survey.getQuestionByName('satisfaction');
q.mininumRateDescription = yourvalue;
survey.render();

Maximum Rate Description: (default is empty) .

var q = survey.getQuestionByName('satisfaction');
q.maximumRateDescription = yourvalue;
survey.render();

Rate values: (default is empty)

var q = survey.getQuestionByName('satisfaction');
q.rateValues = yourvalue;
survey.render();