Hight Quality Salesforce JavaScript-Developer-I Dumps

All JavaScript-Developer-I Related Certification Exams

Question # 1

Which option is true about the strict mode in imported modules?

A. Add the statement use non-strict, before any other statements in the module to enablenot-strict mode.
B. You can only reference notStrict() functions from the imported module.
C. Imported modules are in strict mode whether you declare them as such or not.
D. Add the statement use strict =false; before any other statements in the module to enablenot- strict mode.

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Question # 2

Which two console logs outputs NaN?Choose 2 answers

A. console.log(10/ Number(‘5’));
B. console.log(parseInt(‘two’));
C. console.log(10/ ‘’five);
D. console.log(10/0);

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Question # 3

Which two console logs outputs NaN?Choose 2 answers

A. console.log(10/ Number(‘5’));
B. console.log(parseInt(‘two’));
C. console.log(10/ ‘’five);
D. console.log(10/0);

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Question # 4

Which statement phrases successfully?

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

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Question # 5

developer wants to use a module nameduniversalContainersLib and them call functionsfrom it.How should a developer import every function from the module and then call the fuctionsfooand bar ?

A. import * ad lib from ‘/path/universalContainersLib.js’;lib.foo();lib.bar();
B. import (foo, bar) from ‘/path/universalContainersLib.js’;foo();bar();
C. import all from ‘/path/universalContaineraLib.js’;universalContainersLib.foo();universalContainersLib.bar();
D. import * from ‘/path/universalContaineraLib.js’;universalContainersLib.foo();universalContainersLib.bar();

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Question # 6

Refer to the code below?LetsearchString = ‘ look for this ’;Which two options remove the whitespace from the beginning of searchString?Choose 2 answers

A. searchString.trimEnd();
B. searchString.trimStart();
C. trimStart(searchString);
D. searchString.replace(/*\s\s*/, ‘’);

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Question # 7

Which statement accurately describes an aspect of promises?

A. Arguments for the callback function passed to .then() are optional.
B. In a.then() function, returning results is not necessary since callbacks will catch theresult of a previous promise.
C. .then() cannot be added after a catch.
D. .then() manipulates and returns the original promise.

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Question # 8

Refer to the code below: What is the value of result when the code executes?

A. 10-10
B. 5-5
C. 10-5
D. 5-10

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Question # 9

Given the following code:Let x =null;console.log(typeof x);What is the output of the line 02?

A. “Null”
B. “X”
C. “Object”
D. “undefined”

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Question # 10

A developer is creating a simple webpage with a button. When a userclicks this button for the first time, a message is displayed.The developer wrote the JavaScript code below, but something is missing. Themessage gets displayed every time a user clicks the button, instead of just the first time.01 functionlisten(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, useevent.stopPropagation ( ),
C. On line 04, use button.removeEventListener(‘ click” , listen);
D. On line 06, add an option called once to button.addEventListener().

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Question # 11

A test has a dependency on database. query. During the test, the dependency is replacedwith an object called database with the method,Calculator query, that returns an array. The developer does notneed to verify how manytimes the method has been called.Which two test approaches describe the requirement?Choose 2 answers

A. White box
B. Stubbing
C. Black box
D. Substitution

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Question # 12

Why would a developer specify a package.jason as a developed forge instead of adependency ?

A. It is required by the application in production.
B. It is only needed for local development and testing.
C. Other requiredpackages depend on it for development.
D. It should be bundled when the package is published.

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Question # 13

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 2completed”));04 let car3 = new Promise(resolve => setTimeout (resolve, 3000, “Car 3Completed”));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.

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Question # 14

is the output of line 02?

A. ''x''
B. ''null'''
C. ''object''
D. ''undefined''

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Question # 15

A developer has a formatName function that takes two arguments, firstName and lastNameand returns a string. They want to schedule thefunction to run once after five seconds.What is the correct syntax to schedule this function?

A. setTimeout (formatName(), 5000, "John", "BDoe");
B. setTimeout (formatName('John', ‘'Doe'), 5000);
C. setTimout(() => { formatName("John', 'Doe') }, 5000);
D. setTimeout ('formatName', 5000, 'John", "Doe');

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Question # 16

Refer to the code below:Const resolveAfterMilliseconds = (ms) => Promise.resolve (setTimeout (( => console.log(ms), ms ));Const aPromise = await resolveAfterMilliseconds(500);Const bPromise = await resolveAfterMilliseconds(500);Await aPromise, wait bPromise;What is the result of runningline 05?

A. aPromise and bPromise run sequentially.
B. Neither aPromise or bPromise runs.
C. aPromise and bPromise run in parallel.
D. Only aPromise runs.

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Question # 17

A class was written to represent items for purchase in an online store, and a second class Representing items that are on sale at a discounted price. THe constructor sets the nameto the first value passed in. The pseudocode is below: Class Item { constructor(name, price) { … // ConstructorImplementation } } Class SaleItem extends Item { constructor (name, price, discount) { ...//Constructor Implementation } } There is a new requirement for a developer to implement a description method that will return a brief description for Item and SaleItem.Let regItem =new Item(‘Scarf’, 55); Let saleItem = new SaleItem(‘Shirt’ 80, -1); Item.prototype.description = function () { return ‘This is a ’ + this.name; console.log(regItem.description());console.log(saleItem.description()); SaleItem.prototype.description = function () { return ‘This is a discounted ’ + this.name; } console.log(regItem.description()); console.log(saleItem.description());What is the output when executing the code above ?

A. This is a Scarf Uncaught TypeError:saleItem.description is not a function This is aScarf This is a discounted Shirt
B. This is a Scarf This is a Shirt This is a Scarf This is a discounted Shirt
C. This is a Scarf This is a Shirt This is a discounted Scarf This is a discounted Shirt
D. Thisis aScarf Uncaught TypeError: saleItem.description is not a function This is a Shirt This is a did counted Shirt

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Question # 18

Refer to the code below: let o = { get js() { let city1 = String("st. Louis"); let city2 = String(" New York"); return { firstCity: city1.toLowerCase(), secondCity: city2.toLowerCase(), } } }What value can a developer expect when referencing o.js.secondCity?

A. Undefined
B. ‘ new york ’
C. ‘ New York ’
D. An error

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Question # 19

A team that works on a big project uses npm to deal with projects dependencies.A developer added a dependency does not get downloaded when they executenpminstall.Which two reasons could be possible explanations for this?Choose 2 answers

A. The developer missed the option --add when adding the dependency.
B. The developer added the dependency as a dev dependency, and NODE_ENV Is set to production.
C. The developer missed the option --save when adding the dependency.
D. The developer added the dependency as a dev dependency, and NODE_ENV is set to production.

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Question # 20

Given the code below: 01 function GameConsole (name) { 02 this.name = name; 03 } 04 05 GameConsole.prototype.load = function(gamename) { 06 console.log( ` $(this.name) is loading agame : $(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 cartridgegame: 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) {

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Question # 21

A developer at Universal Containers creates a new landing page based on HTML, CSS, and JavaScript TO ensure that visitors have a good experience, a script named personaliseContextneeds to be executed when the webpage is fully loaded (HTML content and all related files ), in order to do some custom initialization.Which statement should beused to call personalizeWebsiteContent based on the above business requirement?

A. document.addEventListener(‘’onDOMContextLoaded’, personalizeWebsiteContext);
B. window.addEventListener(‘load’,personalizeWebsiteContext);
C. window.addEventListener(‘onload’, personalizeWebsiteContext);
D. Document.addEventListener(‘‘’DOMContextLoaded’ , personalizeWebsiteContext);

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Question # 22

In the browser, the window object is often used to assign variables that require thebroadest scope in an application Node.js application does not have access to the windowobject by default.Which two methods are used to address this ?Choose 2 answers

A. Use the document object instead of the window object.
B. Assign variables to the global object.
C. Create a new window object in the root file.
D. Assign variablesto module.exports and require them as needed.

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Question # 23

Which three browser specific APIs are available for developers to persist data betweenpage loads ?Choose 3 answers

A. IIFEs
B. indexedDB
C. Global variables
D. Cookies
E. localStorage.

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Question # 24

After executing, what is the value offormattedDate?

A. May 10, 2020
B. June 10, 2020
C. October 05, 2020
D. November 05, 2020

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Question # 25

A developer wrote the following code: 01 let X = object.value; 02 03 try { 04 handleObjectValue(X); 05 } catch (error) { 06 handleError(error); 07 }The developer has a getNextValue function to execute after handleObjectValue(), but does not want to execute getNextValue() if an error occurs.How can the developer change the code to ensure thisbehavior?

A. 03 try{ 04 handleObjectValue(x); 05 } catch(error){ 06 handleError(error); 07 } then { 08 getNextValue(); 09 }
B. 03 try{ 04 handleObjectValue(x); 05 } catch(error){ 06 handleError(error); 07 } finally { 08 getNextValue(); 10 }
C. 03 try{ 04handleObjectValue(x); 05 } catch(error){ 06 handleError(error); 07 } 08 getNextValue();
D. 03 try { 04 handleObjectValue(x) 05 ……………………

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Question # 26

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) {

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Question # 27

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 .

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Question # 28

Which function should a developer use to repeatedly execute code at a fixed interval ?

A. setIntervel
B. setTimeout
C. setPeriod
D. setInteria

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Question # 29

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;

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Question # 30

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 ]--

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Question # 31

What can the developer do to change the code to print “Hello World” ?

A. Changeline 7 to ) () ;
B. Change line 2 to console.log(‘Hello’ , name() );
C. Change line 9 to sayHello(world) ();
D. Change line 5 to function world ( ) {

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Question # 32

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

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Question # 33

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) ;

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Question # 34

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

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Question # 35

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’)

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Question # 36

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

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Question # 37

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() {

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Question # 38

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’ } }

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Question # 39

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()

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Question # 40

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.

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Question # 41

Universal Containers (UC) just launched a new landing page, but users complain that thewebsite is slow. A developer found some functions any that might cause this problem. Toverify this, the developer decides to execute everything and log the time each of thesethree suspicious functions consumes.Which function can the developer use to obtain the time spent by every one of the threefunctions?

A. console. timeLog ()
B. console.timeStamp ()
C. console.trace()
D. console.getTime ()

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Question # 42

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’]

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Question # 43

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() {

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Question # 44

Considering type coercion, what does the following expression evaluate to?True + ‘13’ + NaN

A. ‘ 113Nan ’
B. 14
C. ‘ true13 ’
D. ‘ true13NaN ’

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