Salesforce Salesforce Certifications JAVASCRIPT-DEVELOPER-I Questions & Answers

• Question 211:

  Refer to the following array:

  Let arr = [1, 2, 3, 4, 5];

  Which three options result in x evaluating as [1, 2]?

  Choose 3 answer

  A. let x = arr. slice (2);

  B. let x = arr. slice (0, 2);

  C. let x arr.filter((a) => (return a <= 2 });

  D. let x = arr.filter ((a) => 2 }) ;

  E. let x =arr.splice(0, 2);

  Correct Answer: BCE

• Question 212:

  Given the expressions var1 and var2,what are two valid ways to return the concatenation of the two expressions and ensure it is string? Choose 2 answers

  A. var1 + var2

  B. var1.toString ( ) var2.toString ( )

  C. String (var1) .concat (var2)

  D. string.concat (var1 +var2)

  Correct Answer: BD

• Question 213:

  The developer wants to test this code:

  Const toNumber =(strOrNum) => strOrNum;

  Which two tests are most accurate for this code?

  Choose 2 answers

  A. console.assert(toNumber(`2') === 2);

  B. console.assert(Number.isNaN(toNumber()));

  C. console.assert(toNumber(`-3') < 0);

  D. console.assert(toNumber () === NaN);

  Correct Answer: AC

• Question 214:

  Referto the code below: Const pi = 3.1415326, What is the data type of pi?

  A. Double

  B. Number

  C. Decimal

  D. Float

  Correct Answer: B

• Question 215:

  Given code below:

  setTimeout (() => (

  console.log(1);

  ). 0);

  console.log(2);

  New Promise ((resolve, reject )) = > (

  setTimeout(() => (

  reject(console.log(3));

  ). 1000);

  )).catch(() => (

  console.log(4);

  ));

  console.log(5);

  What is logged to the console?

  A. 2 1 4 3 5

  B. 2 5 13 4

  C. 1 2 4 3 5

  D. 1 2 5 3 4

  Correct Answer: B

• Question 216:

  A developer is leading the creation of a new web server for their team that will fulfill API requests from an existing client.

  The team wants a web server that runs on Node.Js, and they want to use the new web framework Minimalist.Js. The lead developer wants to advocate for a more seasoned back- end framework that already has a community around it.

  Which two frameworks could the lead developer advocate for?

  Choose 2 answers

  A. Gatsby

  B. Angular

  C. Express

  D. Koa

  Correct Answer: BC

• Question 217:

  Given the following code: Let x =(`15' + 10)*2;

  What is the value of a?

  A. 3020

  B. 1520

  C. 50

  D. 35

  Correct Answer: A

• Question 218:

  Given the following code:

  Let x =null;

  console.log(typeof x);

  What is the output of the line 02?

  A. "Null"

  B. "X"

  C. "Object"

  D. "undefined"

  Correct Answer: C

• Question 219:

  Which code statement correctly retrieves and returns an object from localStorage?

  A. const retrieveFromLocalStorage = () =>{ return JSON.stringify(window.localStorage.getItem(storageKey)); }

  B. const retrieveFromLocalStorage = (storageKey) =>{ return window.localStorage.getItem(storageKey); }

  C. const retrieveFromLocalStorage = (storageKey) =>{ return JSON.parse(window.localStorage.getItem(storageKey)); }

  D. const retrieveFromLocalStorage = (storageKey) =>{ return window.localStorage[storageKey]; }

  Correct Answer: C

• Question 220:

  In the browser, the window object is often used to assign variables that require the broadest scope in an application Node.js application does not have access to the window object by default.

  Which two methods are used to address this ?

  Choose 2 answers

  A. Use the document object instead of the window object.

  B. Assign variables to the global object.

  C. Create a new window object in the root file.

  D. Assign variables to module.exports and require them as needed.

  Correct Answer: B