Salesforce Certified JavaScript Developer - Multiple Choice (JS-Dev-101) Free Practice Test

Question 1

Refer to the following code (correcting the missing template literal backticks):
let codeName = 'Bond';
let sampleText = `The name is ${codeName}, Jim ${codeName}`;
A developer is trying to determine if a certain substring is part of a string.
Which three code statements return true?

A. sampleText.includes('Jim', 4);

B. sampleText.substring('Jim');

C. sampleText.indexOf('Bond') !== -1;

D. sampleText.includes('The', 1);

E. sampleText.includes('Jim');

Correct Answer: A,C,E

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Question 2

Given two expressions, exp1 and exp2, which two valid ways return the logical AND of the two expressions and ensure it is a Boolean?

A. exp1 & exp2

B. Boolean(exp1 && exp2)

C. Boolean(var1) && Boolean(var2)

D. Boolean(exp1) && Boolean(exp2)

Correct Answer: B,D

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Question 3

Refer to the code below:
01 let first = 'Who';
02 let second = 'What';
03 try {
04 try {
05 throw new Error('Sad trombone');
06 } catch (err) {
07 first = 'Why';
08 throw err;
09 } finally {
10 second = 'When';
11 }
12 } catch (err) {
13 second = 'Where';
14 }
What are the values for first and second once the code executes?

A. first is Who and second is When.

B. first is Why and second is When.

C. first is Why and second is Where.

D. first is Who and second is Where.

Correct Answer: C

Explanation: Only visible for TestSimulate members. You can sign-up / login (it's free).

Question 4

A developer needs the function personalizeWebsiteContent to run when the webpage is fully loaded (HTML and all external resources).
Which implementation should be used?

A. Add a handler to the personalizeWebsiteContent script to handle the DOMContentLoaded event

B. Add a listener to the window object to handle the DOMContentLoaded event

C. Add a listener to the window object to handle the load event

D. Add a handler to the personalizeWebsiteContent script to handle the load event

Correct Answer: C

Explanation: Only visible for TestSimulate members. You can sign-up / login (it's free).

Question 5

Refer to the code below:
01 const addBy = ?
02 const addByEight = addBy(8);
03 const sum = addByEight(50);
Which two functions can replace line 01 and return 58 to sum?

A. const addBy = function(num1) {
return function(num2) {
return num1 + num2;
}
}

B. (Corrected for typing errors)
const addBy = (num1) => {
return function(num2) {
return num1 + num2;
}

C. const addBy = (num1) => num1 + num2;

D. const addBy = function(num1) {
return num1 * num2;
}

Correct Answer: A,B

Explanation: Only visible for TestSimulate members. You can sign-up / login (it's free).

Question 6

A test searches for:
<button class="blue">Checkout</button>
But the actual HTML is:
<button>Checkout</button>
The test fails because it expects a class that no longer exists.
What type of test outcome is this?

A. False negative

B. False positive

C. True positive

D. True negative

Correct Answer: A

Explanation: Only visible for TestSimulate members. You can sign-up / login (it's free).

Question 7

Given a value, which three options can a developer use to detect if the value is NaN?

A. value !== value

B. value == NaN

C. Object.is(value, NaN)

D. value === Number.NaN

E. Number.isNaN(value)

Correct Answer: A,C,E

Question 8

Refer to the following object:
const dog = {
firstName: 'Beau',
lastName: 'Boo',
get fullName() {
return this.firstName + ' ' + this.lastName;
}
};
How can a developer access the fullName property for dog?

A. dog.fullName()

B. dog.function.fullName()

C. dog.get.fullName

D. dog.fullName

Correct Answer: D

Explanation: Only visible for TestSimulate members. You can sign-up / login (it's free).

Question 9

Refer to the HTML below:
<div id="main">
<ul>
<li>Leo</li>
<li>Tony</li>
<li>Tiger</li>
</ul>
</div>
Which JavaScript statement results in changing "Leo" to "The Lion"?

A. document.querySelector('#main li:second-child').innerHTML = 'The Lion';

B. document.querySelector('#main li:nth-child(1)').innerHTML = 'The Lion';

C. document.querySelectorAll('#main li,Leo').innerHTML = 'The Lion';

D. document.querySelectorAll('#main #Leo').innerHTML = 'The Lion';

Correct Answer: B

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Salesforce Certified JavaScript Developer - Multiple Choice (JS-Dev-101) Free Practice Test