Salesforce-JavaScript-Developer Exam Questions With Explanations

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Salesforce Salesforce-JavaScript-Developer Exam Sample Questions 2025

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22214 already prepared
Salesforce Spring 25 Release
221 Questions
4.9/5.0

Which two code snippets show working examples of a recursive function?
(Choose 2 answers)

A. Let countingDown = function(startNumber) {
If ( startNumber >0) {
console.log(startNumber) ;
return countingDown(startNUmber);
} else {
return startNumber;
}};

B. Function factorial ( numVar ) {
If (numVar < 0) return;
If ( numVar === 0 ) return 1;
return numVar -1;

C. Const sumToTen = numVar => {
If (numVar < 0)
Return;
return sumToTen(numVar + 1)};

D. Const factorial =numVar => {
If (numVar < 0) return;
If ( numVar === 0 ) return 1;

A.   Let countingDown = function(startNumber) {
If ( startNumber >0) {
console.log(startNumber) ;
return countingDown(startNUmber);
} else {
return startNumber;
}};
D.   Const factorial =numVar => {
If (numVar < 0) return;
If ( numVar === 0 ) return 1;

Explanation:

Option A shows a proper recursive countdown function that:
Has a base case (startNumber <= 0)
Makes a recursive call with a modified parameter (startNumber - 1)
Actually progresses toward the base case

Option D shows a correct factorial function that:
Handles edge cases (negative numbers and 0)
Recursively calls itself with numVar - 1
Combines results with multiplication (numVar * factorial(numVar - 1))

is below:

< img src=”” height=”200” alt=”Image Preview…”/>
The JavaScript portion is:

01 functionpreviewFile(){
02 const preview = document.querySelector(‘img’);
03 const file = document.querySelector(‘input[type=file]’).files[0];
04 //line 4 code
05 reader.addEventListener(“load”, () => {
06 preview.src = reader.result;
07 },false);
08 //line 8 code
09 }

In lines 04 and 08, which code allows the user to select an image from their local computer , and to display the image in the browser?

A. 04 const reader = new File(); 08 if (file) URL.createObjectURL(file);

B. 04 const reader = new FileReader(); 08 if (file) URL.createObjectURL(file);

C. 04 const reader = new File(); 08 if (file) reader.readAsDataURL(file);

B.   04 const reader = new FileReader(); 08 if (file) URL.createObjectURL(file);

Explanation:

You need to create a FileReader instance to handle file input and then generate a temporary URL for the selected file so the browser can display it. At line 04 you write:
const reader = new FileReader();
This gives you a reader that can process file blobs. Then at line 08 you check for a file and generate an object URL:
if (file) preview.src = URL.createObjectURL(file);
URL.createObjectURL(file) creates a blob URL pointing to the user’s local file, which you assign directly to the ’s src. This pattern is efficient and widely supported for image previews.

A developer wrote the following code to test a sum3 function that takes in an array of numbers and returns the sum of the first three numbers in the array, and the test passes. A different developer made changes to the behavior of sum3 to instead sum only the first two numbers present in the array

Which two results occur when running this test on the updated sum3 function?
Choose 2 answers

A. The line 05 assertion passes.

B. The line 02 assertion passes.

C. The line 02 assertion fails.

D. The line 05 assertion fails.

B.   The line 02 assertion passes.
D.   The line 05 assertion fails.

Refer to the code below

Which value can a developer expect when referencing country,capital,cityString?

A. 'London'

B. undefined

C. An error

D. 'NaN'

D.   'NaN'

developer removes the HTML class attribute from the checkout button, so now it is simply:
.
There is a test to verify the existence of the checkout button, however it looks for a button with class= “blue”. The test fails because no such button is found.
Which type of test category describes this test?

A. True positive

B. True negative

C. False positive

D. False negative

D.   False negative

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