Salesforce Salesforce Certifications JAVASCRIPT-DEVELOPER-I Questions & Answers

• Question 71:

  developer is trying to convince management that their team will benefit from using Node.js for a backend server that they are going to create. The server will be a web server that handles API requests from a websitethat the team has already

  built using HTML, CSS, and JavaScript.

  Which three benefits of Node.js can the developer use to persuade their manager?

  Choose 3 answers:

  A. Installs with its own package manager to install and manage third-party libraries.

  B. Ensures stability with one major release every few years.

  C. Performs a static analysis on code before execution to look for runtime errors.

  D. Executes server-side JavaScript code to avoid learning a new language.

  E. Uses non-blocking functionality for performant request handling .

  Correct Answer: ACE

• Question 72:

  Which code statement below correctly persists an objects inlocal Storage ?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: A

• Question 73:

  A developer is setting up a new Node.js server with a client library that is built using events and callbacks.

  The library:

  Will establish a web socket connection and handle receipt of messages to the server Will be imported with require, and made available with a variable called we.

  The developer also wants to add error logging if a connection fails.

  Given this info, which code segment shows the correct way to set up a client with two events that listenat execution time?

  A. ws.connect (( ) => { console.log(`connected to client'); }).catch((error) => { console.log(`ERROR' , error); }};

  B. ws.on (`connect', ( ) => { console.log(`connected to client'); ws.on(`error', (error) => { console.log(`ERROR' ,error); }); }); C. ws.on (`connect', ( ) => { console.log(`connected to client'); }}; ws.on(`error', (error) => { console.log(`ERROR' , error); }};

  C. try{ ws.connect (( ) => { console.log(`connected to client'); }); } catch(error) { console.log(`ERROR' ,error); }; }

  Correct Answer: C

• Question 74:

  Given the code below:

  Setcurrent URL ();

  console.log(`The current URL is: ` +url );

  functionsetCurrentUrl() {

  Url = window.location.href:

  What happens when the code executes?

  A. The url variable has local scope and line 02 throws an error.

  B. The url variable has global scope and line 02 executes correctly.

  C. The url variable has global scope and line 02 throws an error.

  D. The url variable has local scope and line 02 executes correctly.

  Correct Answer: B

• Question 75:

  Refer to the following code:

  

  What is the output of line 11?

  A. [1,2]

  B. ["bar", "foo"]

  C. ["foo:1", "bar:2"]

  D. ["foo", "bar"]

  Correct Answer: D

• Question 76:

  Refer to code below:

  Const objBook = {

  Title: `Javascript',

  };

  Object.preventExtensions(objBook);

  Const newObjBook = objBook;

  newObjectBook.author = `Robert';

  What are the values of objBook and newObjBook respectively?

  A. [title: "javaScript"] [title: "javaScript"]

  B. {author: "Robert", title: "javaScript}

  Undefined

  C. {author: "Robert", title: "javaScript} {author: "Robert", title: "javaScript}

  D. {author: "Robert"} {author: "Robert", title: "javaScript}

  Correct Answer: A

• Question 77:

  GIven a value, which three options can a developer use to detect if the value is NaN? Choose 3 answers !

  A. value == NaN

  B. Object.is(value, NaN)

  C. value === Number.NaN

  D. value ! == value

  E. Number.isNaN(value)

  Correct Answer: AE

• Question 78:

  Refer to the code below:

  

  What is the value of result when the code executes?

  A. 10-10

  B. 5-5

  C. 10-5

  D. 5-10

  Correct Answer: A

• Question 79:

  Given the following code:

  Counter = 0;

  const logCounter = () => {

  console.log(counter);

  );

  logCounter();

  setTimeout(logCOunter, 1100);

  setInterval(() => {

  Counter++

  logCounter();

  }, 1000);

  What is logged by the first four log statements?

  A. 0 0 1 2

  B. 0 1 2 3

  C. 0 1 1 2

  D. 0 1 2 2

  Correct Answer: C

• Question 80:

  Refer to the code below:

  Function changeValue(obj) {

  Obj.value =obj.value/2;

  }

  Const objA = (value: 10);

  Const objB = objA;

  changeValue(objB);

  Const result = objA.value;

  What is the value of result after the code executes?

  A. 10

  B. Nan

  C. 5

  D. Undefined

  Correct Answer: C