JS-Dev-101 by Salesforce Actual Free Exam Questions And Answers

Question 1

Which actions can be done using the JavaScript browser console?

A. View and change security cookies

B. Change the DOM and the JavaScript code of the page

C. Display a report showing the performance of a page

D. Run code that's not related to the page

E. View and change the DOM of the page

Discussion 0

Correct Answer: E Vote an answer

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Question 2

Universal Containers (UC) just launched a new landing page, but users complain that the website is slow. A developer found some functions that might cause this problem. To verify this, the developer decides to execute everything and log the time each of these three suspicious functions consumes.
01 console.time('Performance');
02
03 maybeAHeavyFunction();
04
05 thisCouldTakeTooLong();
06
07 orMaybeThisOne();
08
09 console.endTime('Performance');
Which function can the developer use to obtain the time spent by every one of the three functions?

A. console.trace()

B. console.timeLog()

C. console.getTime()

D. console.timeStamp()

Discussion 0

Correct Answer: B Vote an answer

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Question 3

let sampleText = "The quick brown fox jumps";
Which three expressions return true for a substring?

A. sampleText.includes('fox');

B. sampleText.indexOf('quick') > -1;

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

D. sampleText.include('fox') !== -1;

E. sampleText.indexOf('fox') !== -1;

Discussion 0

Correct Answer: A,B,E Vote an answer

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Question 4

A page loads 50+ <div class="ad-library-item"> elements, all ads.
Developer wants to quickly and temporarily remove them.
Options:

A. Use the browser console to execute a script that prevents the load event from firing.

B. Use the DOM inspector to remove all elements containing the class ad-library-item.

C. Use the DOM inspector to prevent the load event from firing.

D. Use the browser console to execute a script that removes all elements containing the class ad-library-item.

Discussion 0

Correct Answer: D Vote an answer

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Question 5

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)

Discussion 0

Correct Answer: B,D Vote an answer

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Question 6

A developer wants to use a module named universalContainerslib and then call functions from it. How should a developer import every function from the module and then call the functions foo and bar?

A. import * as lib from '/path/universalContainerslib.js';
lib.foo();
lib.bar();

B. import * from '/path/universalContainerslib.js';
universalContainerslib.foo();
universalContainerslib.bar();

C. import all from '/path/universalContainerslib.js';
universalContainerslib.foo();
universalContainerslib.bar();

D. import {foo, bar} from '/path/universalContainerslib.js';
foo();
bar();

Discussion 0

Correct Answer: A Vote an answer

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Question 7

A developer needs to debug a Node.js web server because a runtime error keeps occurring at one of the endpoints.
The developer wants to test the endpoint on a local machine and make the request against a local server to look at the behavior. In the source code, the server.js file will start the server. The developer wants to debug the Node.js server only using the terminal.
Which command can the developer use to open the CLI debugger in their current terminal window?
(With corrected typing errors: node_inspect → node inspect, node_start_inspect → node start inspect.)

A. node server.js --inspect

B. node -i server.js

C. node inspect server.js

D. node start inspect server.js

Discussion 0

Correct Answer: C Vote an answer

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Salesforce Certified JavaScript Developer - Multiple Choice - JS-Dev-101 Exam Practice Test

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