js-readme-node.js

var client = require('swagger-client');

var swagger = new client({
  url: 'http://petstore.swagger.io/v2/swagger.json',
  success: function() {

    swagger.apis.pet.getPetById({petId:10},function(pet){
      console.log('pet', pet);
    });

  }
})

output.txt

// Output from running js-readme-node.js
// ..having assigned a pet with ID = 10

pet { url: 'http://petstore.swagger.io/v2/pet/10',
  method: 'GET',
  headers: 
   { 'access-control-allow-origin': '*',
     'access-control-allow-methods': 'GET, POST, DELETE, PUT',
     'access-control-allow-headers': 'Content-Type, api_key, Authorization',
     'content-type': 'application/xml',
     connection: 'close',
     server: 'Jetty(9.2.7.v20150116)' },
  obj: {},
  status: 200,
  statusText: undefined,
  data: undefined }