Salesforce Salesforce Certifications JAVASCRIPT-DEVELOPER-I Questions & Answers

• Question 91:

  Refer to the code below?

  Let searchString = ` look forthis ';

  Which two options remove the whitespace from the beginning of searchString?

  Choose 2 answers

  A. searchString.trimEnd();

  B. searchString.trimStart();

  C. trimStart(searchString);

  D. searchString.replace(/*\s\s*/, `');

  Correct Answer: BD

• Question 92:

  A developer has code that calculates a restaurant bill, but generates incorrect answers while testing the code:

  function calculateBill ( items ) {

  let total = 0;

  total += findSubTotal(items);

  total += addTax(total);

  total += addTip(total);

  return total;

  }

  Which option allows the developer to step into each function execution within calculateBill?

  A. Using the debugger commandon line 05.

  B. Using the debugger command on line 03

  C. Calling the console.trace (total) method on line 03.

  D. Wrapping findSubtotal in a console.log() method.

  Correct Answer: A

• Question 93:

  Which three browser specific APIs are available for developers to persist data between page loads? Choose 3 answers

  A. IIFEs

  B. indexedDB

  C. Global variables

  D. Cookies

  E. localStorage.

  Correct Answer: ABE

• Question 94:

  Refer to the code below:

  

  Considering that JavaScript is single-threaded, what is the output of line 08 after the code executes?

  A. 10

  B. 11

  C. 12

  D. 13

  Correct Answer: B

• Question 95:

  A developer is required to write a function that calculates the sum of elements in an array but is getting undefinedevery time the code is executed. The developer needs to find what is missing in the code below.

  Const sumFunction = arr => {

  Return arr.reduce((result, current) => {

  //

  Result += current;

  //

  ), 10);

  );

  Which option makes the code work as expected?

  A. Replace line 02 with return arr.map(( result, current) => (

  B. Replace line 04 with result = result +current;

  C. Replace line 03 with if(arr.length == 0 ) ( return 0; )

  D. Replace line 05 with return result;

  Correct Answer: D

• Question 96:

  A developer wants to iterate through an array of objects and count the objects and count the objects whose property value, name, starts with the letter N. Const arrObj = [{"name" : "Zach"} , {"name" : "Kate"},{"name" : "Alise"},{"name" : "Bob"},

  {"name" : "Natham"},{"name" : "nathaniel"}

  Refer to the code snippet below:

  01 arrObj.reduce(( acc, curr) => {

  02 //missing line 02

  02 //missing line 03

  04 ).0);

  Which missing lines 02 and 03 return the correct count?

  A. Const sum = curr.startsWith(`N') ? 1: 0; Return acc +sum

  B. Const sum = curr.name.startsWith(`N') ? 1: 0; Return acc +sum

  C. Const sum = curr.startsWIth(`N') ? 1: 0; Return curr+ sum

  D. Constsum = curr.name.startsWIth(`N') ? 1: 0; Return curr+ sum

  Correct Answer: B

• Question 97:

  Refer to the code below:

  new Promise((resolve, reject) => {

  const fraction = Math.random();

  if( fraction >0.5) reject("fraction > 0.5, " + fraction);

  resolve(fraction);

  })

  .then(() =>console.log("resolved"))

  .catch((error) => console.error(error))

  .finally(() => console.log(" when am I called?"));

  

  When does Promise.finally on line 08 get called?

  A. When rejected

  B. When resolved and settled

  C. When resolved

  D. When resolved or rejected

  Correct Answer: D

• Question 98:

  A developer receives a comment from the Tech Lead that the code given below has error:

  const monthName = `July';

  const year = 2019;

  if(year === 2019) {

  monthName= `June';

  }

  Which line edit should be made to make this code run?

  A. 01 let monthName ='July';

  B. 02 let year =2019;

  C. 02 const year = 2020;

  D. 03 if (year == 2019) {

  Correct Answer: A

• Question 99:

  A developer is wondering whether to use, Promise.then or Promise.catch, especially when a Promise throws an error?

  Which two promises are rejected?

  Which 2 are correct?

  A. Promise.reject(`cool error here').then(error => console.error(error));

  B. Promise.reject(`cool error here').catch(error => console.error(error));

  C. New Promise((resolve, reject) => (throw `cool error here'}).catch(error => console.error(error)) ;

  D. New Promise(() => (throw `coolerror here'}).then(null, error => console.error(error)));

  Correct Answer: BC

• Question 100:

  Refer to the code below:

  Let car1 = new Promise((_ , reject) =>

  setTimeout(reject, 2000, "car 1 crashed in" =>

  Let car2 =new Promise(resolve => setTimeout(resolve, 1500, "car 2 completed")

  Let car3 =new Promise(resolve =>setTimeout(resolve, 3000, "car 3 completed")

  Promise.race(( car1, car2, car3))

  .then (value => (

  Let result = `$(value) the race.';)}

  .catch(arr => {

  console.log("Race is cancelled.", err);

  });

  What is the value of result when Promise.race executes?

  A. Car3 completes the race

  B. Car 2 completed the race.

  C. Car 1 crashed in the race.

  D. Race is cancelled.

  Correct Answer: B