UpWork (oDesk) & Elance Node.js Test Question & Answers

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Ques : What do the lines like symbols = symbols || SYMBOLS_DEFAULT; do?

Ans  : This is a JS idiom for setting default arguments.

Ques : True or False: node.js can call other command line scripts.
Ans  : True

Ques :  The "js" in Node.js stands for?
Ans  :  javascript

Ques : Why is Node.js important?
Ans  : It allows asynchronous processing in the background without interupting the user

Ques : Why is Node.js important?
Ans  : It allows asynchronous processing in the background without interupting the user

Ques :  To exit out of a function you should use _____?
Ans  :  return;

Ques : The process object is an instance of what class?
Ans  : EventEmitter

Ques : To create an instance of the HTTP object, which function is used?
Ans  :  require

Ques :True or false? Node.js is multi-core by nature.
Ans  : False

Ques : The process object is an instance of____?
Ans  : EventEmitter

Ques : To parse a URL string use____?
Ans  : querystring

Ques :  The Javascript used in node.js:
Ans  :  Is on-par with a recent version of Chrome

Ques : What program is used to programmtically control the browser?
Ans  : javascript

Ques : Which of the following is a standard node module, included with the default install?
Ans  : fs

Ques : Running the following code, what will the console output?  var http = require('http');   http.createServer(   function (request, response) {     response.writeHead(200, {'Content-Type': 'text/plain'});     response.end('Hello World\n');   } ).listen(8000);   console.log('Server running at http://localhost:8000/');
Ans  :  Server running at http://localhost:8000/

Ques : A module is an____?
Ans  : Object

Ques : How do you call a function attached to an object that will be executed when the object emits an event?
Ans  : Listener

Ques : Node.js is stored on your____?
Ans  :  hard drive

Ques : What is node.js based on?
Ans  : Chrome's JavaScript runtime

Ques :  What is a Buffer?
Ans  :  Raw memory allocated outside the v8 heap

Ques : WebSockets with Socket.io can be used to?
Ans  : All of these.

Ques :  How do you require a module?
Ans  :  var module = require('mymodule')

Ques : Which is a comment in node?
Ans  : //comment

Ques :  Which of the following can be created and managed using node.js?
Ans  : All of these 

Ques : REPL is:
Ans  :  Read-Eval-Print-Loop, a way to interactively run code

Ques : To declare a variable use what keyword?
Ans  : var

Ques : NPM is a...
Ans  :  Package manager

Ques : How do you output to console in node.js?
Ans  : util.log or console.log

Ques :  What function is used to write out application errors/events?
Ans  : console.log

Ques : Which is of the following is a potential advantage of using Node.js?
Ans  :  All of these.

Ques : In node.js you can write and run code in what language?
Ans  :  Javascript

Ques : What Javascript Engine does node.js use?
Ans  : V8

Ques :  Use _____ to step through your code.
Ans  : breakpoints

Ques : If you have a node program called example.js, how would that be excuted?
Ans  : node example.js

Ques : A popular web application for framework for node?
Ans  : express

Ques :In this code:   function myLog(err, data) {   console.log(err, data); }  fs.readFile('/tmp/sample', myLog); The function 'myLog' is used as a(an):
Ans  :  Callback

Ques :  node.js excels at dealing with:
Ans  : I/O-bound tasks

Ques : What does Node.js run on?
Ans  : server

Ques : How does one get access to Node.js?
Ans  : download the install

Ques : What is REPL?
Ans  :  Read-Eval-Print-Loop

Ques : The Cryptography module requires OpenSSL.
Ans  : True

Ques : How can I call an object function from my module if my module name is "iModule"?
Ans  :  require('iModule').mObject();

Ques : Where does Node run on your machine?
Ans  : as an application

Ques : If you have a problem with your code, where would you look?
Ans  :  console.log

Ques : What interface is used to access folders on your local drive
Ans  :  fs

Ques : What interface is used to create a server through Node.js
Ans  :  http

Ques : What is the code to access the DNS module?
Ans  :   require('dns');

Ques : Which npm command will load all dependencies in the local node_modules folder?
Ans  : npm install

Ques : How do you cause a function to be invoked at a specified time later?
Ans  : setTimeout(fn, 1000)

Ques :  What does the Zlib module provide?
Ans  : setTimeout(fn, 1000)

Ques : What does the Zlib module provide?
Ans  :  Bindings to Gzip/Gunzip, Deflate/Inflate, and DeflateRaw/InflateRaw classes

Ques : What does the require call return?
Ans  : module.exports object

Ques :  What method is used to parse JSON using NodeJS?
Ans  :  JSON.parse();

Ques : What is node.js?
Ans  :  A program written in C

Ques : In the following Express route stack, which handler will be called for "GET /item/23"?  app.get("/", routes.index ); app.get("/item", routes.item ); app.get("/item/:id", routes.id ); app.post("/item/:id", routes.post );
Ans  : routes.id

Ques :  Which of these is a built-in module that can be used for unit testing in Node.js?
Ans  : Assert

Ques : How do you start the node.js REPL?
Ans  :  node

Ques : True or False: node.js runs in a single thread.
Ans  :  True

Ques : Which function allows you to chain event listeners?
Ans  :  on()

Ques : The interactive shell is also called_____?
Ans  :  REPL

Ques : What syntax is correct for reading environment variable?
Ans  : process.env.ENV_VARIABLE

Ques : Timer functions are built into node.js, you do not need to require() this module in order to use them.
Ans  :  true

Ques : Which of these statements about Express is true?
Ans  :  Express is an NPM module.

Ques : Which company manages and maintains node.js?
Ans  :  Joyent

Ques : Given the following route and request, which Request object property will hold the value of 30 in the Express handler?  Route: "/post/:id" Request: "/post/30?start=20"
Ans  :  req.params.id

Ques : net.Server emits an event every time a ____ connects to the server.
Ans  :  peer

Ques : By executing node without any arguments from the command-line:
Ans  :  you will be dropped into the REPL

Ques : Which of these are valid ways to apply middleware in Express?
Ans  :  All of these.

Ques : What built in class is a global type for dealing with binary data directly?
Ans  : Buffer

Ques : What is typically the first parameter in node.js callback functions?
Ans  : Error

Ques : Node will run until its sure that no further ___ are available.
Ans  : Events-handlers

Ques : If an error occures in an Express middleware function, what is the best way to pass the error object to the subsequent handlers?
Ans  :  function( req, res, next){ ... next( err ); }

Ques : The VM module allows one to:
Ans  : Run JavaScript code in a sandbox environment

Ques : The first argument passed to a Node.js asynchronous callback is always what?
Ans  : An Error object if an error has occured.

Ques : In Express, which of these paths would NOT be cosumed by the following route?  "/users/:id/:action?"
Ans  :  "/users"

Ques : Express middleware is actually handled by what other Node.js module?
Ans  : Connect

Ques : Node.js is a truly parallel technology.
Ans  : False

Ques : Which of these Express middleware stacks will NOT log favicon requests?
Ans  :  app.use(express.favicon()); app.use(express.logger()); app.use(express.static(__dirname + '/public'));

Ques : In Express, which of these Response methods can NOT automatically end the response?
Ans  : res.type()

Ques : Given the following route and request, which Request object property will hold the value of 20 in the Express handler?  Route: "/post/:id" Request: "/post/30?start=20"
Ans  : req.query.start

Ques : var http_server = require('http');  how can you create a server?
Ans  : http_server.createServer(function(){});

Ques : Node.js clusters are child processes that do NOT share server ports?
Ans  : false

Ques : Which of these is definitely true of Node.js?
Ans  : Node.js can be used to create command line tools.

Ques : What command is used to end a Node.JS process?
Ans  :  .exit

Ques : Which of these are required fields in your package.json file?
Ans  : "name" and "version"

Ques : What is the name of the module system used in node.js?
Ans  :  CommonJS

Ques : In Node.js, the result of an asynchronous function can be accessed how?
Ans  : By the value passed as the second argument of the callback.

Ques : What is NOT a valid method to create a child process instance?
Ans  :  popen(3)

Ques : In Express, which of these would NOT expose the variable "title" to the template renderer?
Ans  :  res.render.title = "My App";

Ques : Which Express middleware must come before express.session() in your stack?
Ans  :  express.cookieParser()

Ques : If an EventEmitter object emits an 'error' event and there is no listener for it, node will:
Ans  : Print a stack trace and exit

Ques :  The http.ServerResponse is an example of a what?
Ans  : A writable Stream.

Ques : Which of these is NOT a global object?
Ans  : Stream

Ques : Which of the following is not a global object in node.js?
Ans  : path

Ques :  Which of these is a valid way to output the contents of a file?
Ans  : console.log( fs.readFileSync("file.txt") );

Ques : What is the default memory limit on a node process?
Ans  : 512mb on 32-bit systems, and 1gb on 64-bit systems.

Ques : If the Connect node package module is updated from version 2.8.5 to version 3.1.0 which dependency in your package.json file may break your application on update?
Ans  : "connect": ">=2.5"

Ques : How do you create a new client connection via SSL?
Ans  :  tls.connect()

Ques : In the following Express routing method, what is the maximum number of arguments that may be passed to the callback function "routeHandler"?  app.all("*", routeHandler )
Ans  : 4

Ques : Is it possible to execute node.js system command synchronously?
Ans  : Yes, with a third party library

Ques : When creating a command line tool with Node.js, which expresion will allow you access the first command line argument?
Ans  :  process.argv[2]

Ques : Which of the following is NOT true about Node 0.6?
Ans  : Unix binary distributed

Ques : Which of these is not a valid version according to npm semantic versioning?
Ans  :  "1.2.3b"

Ques : Which is a correct way to check the latest released version of the Express module with npm?
Ans  : npm view express version

Ques :  A Buffer can be resized
Ans  :  False

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