Salesforce JAVASCRIPT DEVELOPER I Exam Questions

Questions for the JAVASCRIPT DEVELOPER I were updated on : Jun 17 ,2024

Page 1 out of 12. Viewing questions 1-15 out of 180

Question 1

Refer to the code below:
01 const exec = (item, delay) =>{
02 new Promise(resolve => setTimeout( () => resolve(item), delay)),
03 async function runParallel() {
04 Const (result1, result2, result3) = await Promise.all{
05 [exec (x, 100) , exec(y, 500), exec(z, 100)]
06 );
07 return `parallel is done: $(result1) $(result2)$(result3)`;
08 }
}
}
Which two statements correctly execute the runParallel () function?
Choose 2 answers

  • A. Async runParallel () .then(data);
  • B. runParallel ( ). done(function(data){ return data; });
  • C. runParallel () .then(data);
  • D. runParallel () .then(function(data) return data
Answer:

B, D

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Question 2

A developer needs to test this function:
01 const sum3 = (arr) => (
02 if (!arr.length) return 0,
03 if (arr.length === 1) return arr[0],
04 if (arr.length === 2) return arr[0] + arr[1],
05 return arr[0] + arr[1] + arr[2],
06 );
Which two assert statements are valid tests for the function?
Choose 2 answers

  • A. console.assert(sum3(1, ‘2’)) == 12);
  • B. console.assert(sum3(0)) == 0);
  • C. console.assert(sum3(-3, 2 )) == -1);
  • D. console.assert(sum3(‘hello’, 2, 3, 4)) === NaN);
Answer:

A, C

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Question 3

Which statement phrases successfully?

  • A. JSON.parse ( ‘ foo ’ );
  • B. JSON.parse ( “ foo ” );
  • C. JSON.parse( “ ‘ foo ’ ” );
  • D. JSON.parse(‘ “ foo ” ’);
Answer:

D

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Question 4

Refer to the code below:
01 let car1 = new promise((_, reject) =>
02 setTimeout(reject, 2000, Car 1 crashed in));
03 let car2 = new Promise(resolve => setTimeout(resolve, 1500, Car 2
completed));
04 let car3 = new Promise(resolve => setTimeout (resolve, 3000, Car 3
Completed));
05 Promise.race([car1, car2, car3])
06 .then(value => (
07 let result = $(value) the race. `;
08 ))
09 .catch( arr => (
10 console.log(Race is cancelled., err);
11 ));
What is the value of result when Promise.race executes?

  • A. Car 3 completed the race.
  • B. Car 1 crashed in the race.
  • C. Car 2 completed the race.
  • D. Race is cancelled.
Answer:

C

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Question 5

Refer to the code below:
for(let number =2 ; number <= 5 ; number += 1 ) {
// insert code statement here
}
The developer needs to insert a code statement in the location shown. The code
statement has these requirements:
1. Does require an import
2. Logs an error when the boolean statement evaluates to false
3. Works in both the browser and Node.js
Which meet the requirements?

  • A. assert (number % 2 === 0);
  • B. console.error(number % 2 === 0);
  • C. console.debug(number % 2 === 0);
  • D. console.assert(number % 2 === 0);
Answer:

B

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Question 6

A developer is working on an ecommerce website where the delivery date is dynamically
calculated based on the current day. The code line below is responsible for this calculation.
Const deliveryDate = new Date ();
Due to changes in the business requirements, the delivery date must now be todays
date + 9 days.
Which code meets this new requirement?

  • A. deliveryDate.setDate(( new Date ( )).getDate () +9);
  • B. deliveryDate.setDate( Date.current () + 9);
  • C. deliveryDate.date = new Date(+9) ;
  • D. deliveryDate.date = Date.current () + 9;
Answer:

A

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Question 7

Which three statements are true about promises ?
Choose 3 answers

  • A. The executor of a new Promise runs automatically.
  • B. A Promise has a .then() method.
  • C. A fulfilled or rejected promise will not change states .
  • D. A settled promise can become resolved.
  • E. A pending promise can become fulfilled, settled, or rejected.
Answer:

B, C, E

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Question 8

Given the code below:
01 function GameConsole (name) {
02 this.name = name;
03 }
05 GameConsole.prototype.load = function(gamename) {
06 console.log( ` $(this.name) is loading a game : $(gamename) `);
07 )
08 function Console 16 Bit (name) {
09 GameConsole.call(this, name) ;
10 }
11 Console16bit.prototype = Object.create ( GameConsole.prototype) ;
12 //insert code here
13 console.log( ` $(this.name) is loading a cartridge game : $(gamename) `);
14 }
15 const console16bit = new Console16bit( SNEGeneziz );
16 console16bit.load( Super Nonic 3x Force );
What should a developer insert at line 15 to output the following message using the
method ?
> SNEGeneziz is loading a cartridge game: Super Monic 3x Force . . .

  • A. Console16bit.prototype.load(gamename) = function() {
  • B. Console16bit.prototype.load = function(gamename) {
  • C. Console16bit = Object.create(GameConsole.prototype).load = function (gamename) {
  • D. Console16bit.prototype.load(gamename) {
Answer:

B

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Question 9

A developer has the following array of student test grades:
Let arr = [ 7, 8, 5, 8, 9 ];
The Teacher wants to double each score and then see an array of the students
who scored more than 15 points.
How should the developer implement the request?

  • A. Let arr1 = arr.filter(( val) => ( return val > 15 )) .map (( num) => ( return num *2 ))
  • B. Let arr1 = arr.mapBy (( num) => ( return num *2 )) .filterBy (( val ) => return val > 15 )) ;
  • C. Let arr1 = arr.map((num) => num*2). Filter (( val) => val > 15);
  • D. Let arr1 = arr.map((num) => ( num *2)).filterBy((val) => ( val >15 ));
Answer:

C

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Question 10

A test has a dependency on database.query. During the test the dependency is replaced
with an object called database with the method, query, that returns an array. The
developer needs to verify how many times the method was called and the arguments
used each time.
Which two test approaches describe the requirement?
Choose 2 answers

  • A. Integration
  • B. Black box
  • C. White box
  • D. Mocking
Answer:

C, D

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Question 11

Given the JavaScript below:
01 function filterDOM (searchString) {
02 const parsedSearchString = searchString && searchString.toLowerCase() ;
03 document.quesrySelectorAll( .account ) . forEach(account => (
04 const accountName = account.innerHTML.toLOwerCase();
05 account. Style.display = accountName.includes(parsedSearchString) ? /*Insert
code*/;
06 )};
07 }
Which code should replace the placeholder comment on line 05 to hide accounts that do
not match the search string?

  • A. ‘ name ’ : ‘ block ’
  • B. ‘ Block ’ : ‘ none ’
  • C. ‘ visible ’ : ‘ hidden ’
  • D. ‘ hidden ’ : ‘ visible ’
Answer:

B

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Question 12

developer publishes a new version of a package with new features that do not break
backward compatibility. The previous version number was 1.1.3.
Following semantic versioning format, what should the new package version number
be?

  • A. 2.0.0
  • B. 1.2.3
  • C. 1.1.4
  • D. 1.2.0
Answer:

D

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Question 13

A developer is creating a simple webpage with a button. When a user clicks this button
for the first time, a message is displayed.
The developer wrote the JavaScript code below, but something is missing. The
message gets displayed every time a user clicks the button, instead of just the first time.
01 function listen(event) {
02 alert ( Hey! I am John Doe) ;
03 button.addEventListener (click, listen);
Which two code lines make this code work as required?
Choose 2 answers

  • A. On line 02, use event.first to test if it is the first execution.
  • B. On line 04, use event.stopPropagation ( ),
  • C. On line 04, use button.removeEventListener(‘ click” , listen);
  • D. On line 06, add an option called once to button.addEventListener().
Answer:

C, D

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Question 14

A developer uses a parsed JSON string to work with user information as in the block below:
01 const userInformation ={
02 id : user-01,
03 email : [email protected],
04 age : 25
Which two options access the email attribute in the object?
Choose 2 answers

  • A. userInformation(“email”)
  • B. userInformation.get(“email”)
  • C. userInformation.email
  • D. userInformation(email)
Answer:

A, C

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Question 15

Refer to the code below:
01 const server = require(server);
02 /* Insert code here */
A developer imports a library that creates a web server. The imported library uses events and
callbacks to start the servers
Which code should be inserted at the line 03 to set up an event and start the web server ?

  • A. Server.start ();
  • B. server.on(‘ connect ’ , ( port) => { console.log(‘Listening on ’ , port) ;})
  • C. server()
  • D. serve(( port) => (
  • E. console.log( ‘Listening on ’, port) ;
Answer:

B

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