oDesk Node.js Test Answers 2015

·


1. Which of the following statements is true about the process object in Node.js?
Answers:
• It is a local object.
• It is an instance of the events.EventEmitter class.
• The process.exit(1) method ends the process with a "success" code.
• "process.stderr" and "process.stdout" are non-blocking if they refer to regular files or TTY file descriptors.

2. Which of the following will synchronously check if a file/directory exists?
Answers:
• fs.exists()
• fs.existsSync()
• fs.checkFileSync()
• fs.checkDirSync()
3. Which of the following will copy a file in Node.js?
Answers:
• var fs = require('fs'); fs.createReadStream('test.file').pipe(fs.createWriteStream('newFile.file'));
• var fs = require('fs'); fs.createReadBuffer('test.file').pipe(fs.createWriteBuffer('newFile.file'));
• var fs = require('file'); fs.createFileReader('test.file').pipe(fs.createFileWriter('newFile.file'));
• var fs = require('fs'); fs.createReadBuffer('test.file').stream(fs.createWriteBuffer('newFile.file'));
4. Which of the following statements are true about the module.exports object in Node.js?
Answers:
• It is the object that gets returned from a require() call.
• It can be assigned in a callback.
• Assigning an export object to module.exports will rebind the local exports variable.
• None of these.
5. Which of the following will open a file, then read its contents one line at a time?
Answers:
• fs.readFileStream()
• fs.readFile()
• fs.createReadStream()
• fs.createFileStream()
6. Which of the following statements is true about the console Object in Node.js?
Answers:
• "console.log" can take only a single argument.
• "console.log" prints to stdout without a newline.
• Its functions are synchronous when the destination is a terminal or a file, and and asynchronous when it's a pipe.
• Its functions are asynchronous when the destination is a terminal or a file, and and synchronous when it's a pipe.
7. Which Node.js module can be used to get the IP address of the server the program is running on?
Answers:
• util
• os
• dns
• net
8. What does the following code do?

var http = require('http');
var fs = require('fs');

var file = fs.createWriteStream("file.png");
var request = http.get("http://path/to/file.png", function(response) {
  response.pipe(file);
});
Answers:
• It creates an HTTP GET request and pipes its response into a writeable file stream.
• It creates an HTTP GET request, and synchronously pipes its response into a writeable file stream.
• It creates an HTTP POST request and pipes its response into a readable file stream.
• It creates an HTTP POST request and pipes its response into a writeable file stream.
9. Which of the following methods can be used to write a file in Node.js?
Answers:
• fs.write()
• fs.writeFile()
• fs.createWriteStream()
• fs.writeStream()
10. Which of the following methods will print to the console without a trailing new line?
Answers:
• process.stdout.print()
• console.error()
• console.log()
• process.stdout.write()
11. Which of the following methods can be used to read the contents of a directory?
Answers:
• fs.readdir()
• fs.readdirSync()
• fs.readDirectory()
• fs.readdirAsync()
12. Which of the following console commands will update all installed global packages to the latest available versions?
Answers:
• npm upgrade -g
• npm install -uga
• npm update -g
• npm version --install-latest
13. Which of the following statements are true about the child_process module in Node.js?
Answers:
• It is not possible to stream data through a child process' stdin, stdout, and stderr in a fully non-blocking way.
• Child processes always have two streams associated with them.
• "require('child_process').spawn()" can be used to create a child process.
• "require('child_process').fork()" can be used to create a child process.
14. Which array contains the command line arguments in Node.js?
Answers:
• process.argv
• args.argv
• arguments.argv
• env.argv
15. Which of the following NPM commands will install both dependencies and devDependencies of a given project?
Answers:
• npm install
• npm install --dev
• npm install --production
• None of these
16. What does the following command do?

npm view <package-name> version
Answers:
• It shows the version of the package installed globally.
• It shows the version of the package installed locally.
• It shows the version of the package that is cached.
• It shows the latest version of the package that is available.
17. Which of the following can be used to get the currently running script's path in Node.js?
Answers:
• __filename
• os.tmpdir()
• path.dirname()
• path.basename()
18. Which of the following can be used to access the environment variable, "ENV_VARIABLE" in Node.js?
Answers:
• process.env.ENV_VARIABLE
• process.argv.ENV_VARIABLE
• process.env.var.ENV_VARIABLE
• process.environment.ENV_VARIABLE
19. What does process.argv[1] contain?
Answers:
• node
• The file path of the JavaScript file.
• The first command line argument.
• The second command line argument.
20. Which of the following command-line arguments to "npm install" will allow an NPM package's binaries to be run outside the project folder?
Answers:
• -g
• --global
• -l
• --link