| Exam Code | Javascript-Developer-I |
| Exam Name | Salesforce Certified JavaScript Developer (JS-Dev-101) |
| Questions | 147 Questions Answers With Explanation |
| Update Date | May 28,2026 |
| Price |
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A developer wants to define a function log to be used a few times on a single-fileJavaScript script.01 // Line 1 replacement02 console.log('"LOG:', logInput);03 }Which two options can correctly replace line 01 and declare the function for use?Choose 2 answers
A. function leg(logInput) {
B. const log(loginInput) {
C. const log = (logInput) => {
D. function log = (logInput) {
A developer wants to create an object from a function in the browser using the codebelow:Function Monster() { this.name =‘hello’ };Const z = Monster();What happens due to lack of the new keyword on line 02?
A. The z variable is assigned the correct object.
B. The z variable is assigned the correct object but this.name remains undefined.
C. Window.name is assigned to ‘hello’ and the variable z remains undefined.
D. Window.m is assigned the correct object.
A developer uses a parsed JSON string to work with userinformation as in the block below:01 const userInformation ={02 “ id ” : “user-01”,03 “email” : “[email protected]”,04 “age” : 25Which 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)
Considering type coercion, what does the following expression evaluate to?True + ‘13’ + NaN
A. ‘ 113Nan ’
B. 14
C. ‘ true13 ’
D. ‘ true13NaN ’
A developer creates a class that represents a blog post based on the requirement that aPost should have a body author and view count.The Code shown Below:ClassPost {// Insert code hereThis.body =bodyThis.author = author;this.viewCount = viewCount;}}Which statement should be inserted in the placeholder on line 02 to allow for a variable tobe setto a new instanceof a Post with the three attributes correctly populated?
A. super (body, author, viewCount) {
B. Function Post (body, author, viewCount) {
C. constructor (body, author, viewCount) {
D. constructor() {
Refer to the code below:Let foodMenu1 =[‘pizza’, ‘burger’, ‘French fries’];Let finalMenu = foodMenu1;finalMenu.push(‘Garlic bread’);What is the value of foodMenu1 after the code executes?
A. [ ‘pizza’,’Burger’, ‘French fires’, ‘Garlic bread’]
B. [ ‘pizza’,’Burger’, ‘French fires’]
C. [ ‘Garlic bread’ , ‘pizza’,’Burger’, ‘French fires’ ]
D. [ ‘Garlic bread’]
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 canbecome fulfilled, settled, or rejected.
A developer creates an object where its properties should be immutable and preventproperties from being added or modified.Which method shouldbe used to execute this business requirement ?
A. Object.const()
B. Object.eval()
C. Object.lock()
D. Object.freeze()
Refer to the code below:const event = new CustomEvent(//Missing Code );obj.dispatchEvent(event);A developer needs to dispatch a custom event called update to send information aboutrecordId.Which two options could a developer insert at the placeholder in line 02 to achieve this?Choose 2 answers
A. ‘Update’ , (recordId : ‘123abc’(
B. ‘Update’ , ‘123abc’
C. { type : ‘update’, recordId : ‘123abc’ }
D. ‘Update’ , { Details : { recordId : ‘123abc’ } }
A developer creates a simple webpage with an input field. When a user enters text in theinput field and clicks the button, the actual value of the field must be displayed in theconsole.Here is the HTML file content:<input type =” text” value=”Hello” name =”input”><button type =”button” >Display </button> The developer wrote the javascript code below:Const button= document.querySelector(‘button’);button.addEvenListener(‘click’, () => (Const input = document.querySelector(‘input’);console.log(input.getAttribute(‘value’));When the user clicks the button, the output is always “Hello”.What needs to be done to make this code work as expected?
A. Replace line 04 with console.log(input .value);
B. Replace line 03 with const input = document.getElementByName(‘input’);
C. Replace line 02 with button.addCallback(“click”, function() {
D. Replace line 02 withbutton.addEventListener(“onclick”, function() {
Refer to the following code:<html lang=”en”><body><div onclick = “console.log(‘Outer message’) ;”><button id =”myButton”>CLick me<button></div></body><script>function displayMessage(ev) {ev.stopPropagation();console.log(‘Inner message.’);}const elem =document.getElementById(‘myButton’);elem.addEventListener(‘click’ , displayMessage);</script></html>What will the console show when the button is clicked?
A. Outer message
B. Outer message Inner message
C. Inner message Outer message
D. Inner message
Refer to the code below:Async funct on functionUnderTest(isOK) {If (isOK) return ‘OK’ ;Throw new Error(‘not OK’);)Which assertion accuretely tests the above code?
A. Console.assert (await functionUnderTest(true), ‘ OK ’)
B. Console.assert (await functionUnderTest(true), ‘ not OK ’)
C. Console.assert (awaitfunctionUnderTest(true), ‘ not OK ’)
D. Console.assert (await functionUnderTest(true), ‘OK’)
A developer writers the code below to calculate the factorial of a given number.Function factorial(number) {Return number + factorial(number -1);}factorial(3);What isthe result of executing line 04?
A. 0
B. 6
C. -Infinity
D. RuntimeError
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 eventsandcallbacks to start the serversWhich 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) ;
A developer wants to iterate through an array of objects and count the objects and countthe 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 0202 //missing line 0304 ).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
Giventhe code below:const copy = JSON.stringify([ new String(‘ false ’), new Bollean( false ), undefined ]);What is the value of copy?
A. -- [ \”false\” , { } ]--
B. -- [ false, { } ]--
C. -- [ \”false\” , false, undefined ]--
D. -- [ \”false\” ,false, null ]--
A developer is working on an ecommerce website where the delivery date is dynamicallycalculated 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 today’sdate + 9 days.Which code meets thisnew 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;
Which function should a developer use to repeatedly execute code at a fixed interval ?
A. setIntervel
B. setTimeout
C. setPeriod
D. setInteria
developer is trying to convince management that their team will benefit from usingNode.js for a backend server that they are going to create. The server will be a web serverthathandles API requests from a website that the team has already built using HTML, CSS,andJavaScript.Which three benefits of Node.js can the developer use to persuade their manager?Choose 3 answers:
A. I nstalls with its own package manager toinstall and manage third-party libraries.
B. Ensures stability with one major release every few years.
C. Performs a static analysis on code before execution to look for runtime errors.
D. Executes server-side JavaScript code to avoid learning a new language.
E. User non blocking functionality for performant request handling .
A developer receives a comment from the Tech Lead that the code given below haserror: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) {
