A developer needs to test this function:01 const sum3 = (arr) => (02 if (!arr.length) return 0,03 if (arr.length === 1) return arr[0],04 if (arr.length === 2) return arr[0] + arr[1],05 return arr[0] + arr[1] + arr[2],06 );Which two assert statements are valid tests for the function?Choose 2 answers

console.assert(sum3(1, '2')) == 12);

console.assert(sum3(-3, 2 )) == -1);

console.assert(sum3(1, '2')) == 12);

console.assert(sum3(-3, 2 )) == -1);

console.assert(sum3('hello', 2, 3, 4)) === NaN);

Refer to the code below: for(let number =2 ; number <= 5 ; number += 1 ) {// insert code statement here}The developer needs to insert a code statement in the location shown. The code statement has these requirements:

Logs an error when the boolean statement evaluates to false

Works in both the browser and Node.jsWhich meet the requirements?

console.error(number % 2 === 0);

console.debug(number % 2 === 0);

console.assert(number % 2 === 0);

A developer is working on an ecommerce website where the delivery date is dynamically calculated 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's date + 9 days.Which code meets this new requirement?

deliveryDate.setDate(( new Date ( )).getDate () +9);

deliveryDate.setDate( Date.current () + 9);

deliveryDate.date = new Date(+9) ;

deliveryDate.date = Date.current () + 9;

Which three statements are true about promises ?Choose 3 answers

A Promise has a .then() method.

A fulfilled or rejected promise will not change states .

A pending promise can become fulfilled, settled, or rejected.

The executor of a new Promise runs automatically.

A Promise has a .then() method.

A fulfilled or rejected promise will not change states .

A settled promise can become resolved.

A pending promise can become fulfilled, settled, or rejected.

Given the code below:01 function GameConsole (name) {02 this.name = name;03 }0405 GameConsole.prototype.load = function(gamename) {06 console.log( ` $(this.name) is loading a game : $(gamename) …`);07 )08 function Console 16 Bit (name) {09 GameConsole.call(this, name) ;10 }11 Console16bit.prototype = Object.create ( GameConsole.prototype) ;12 //insert code here13 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 tooutput the following message using the method ?> SNEGeneziz is loading a cartridge game: Super Monic 3x Force . . .

Console16bit.prototype.load = function(gamename) {

Console16bit.prototype.load(gamename) = function() {

Console16bit.prototype.load = function(gamename) {

Console16bit = Object.create(GameConsole.prototype).load = function(gamename) {

Console16bit.prototype.load(gamename) {

A developer has the following array of student test grades:Let arr = [ 7, 8, 5, 8, 9 ];The Teacher wants to double each score and then see an array of the students who scored more than 15 points.How should the developer implement the request?

Let arr1 = arr.map((num) => num*2). Filter (( val) => val > 15);

Let arr1 = arr.filter(( val) => ( return val > 15 )) .map (( num) => ( return num *2 ))

Let arr1 = arr.mapBy (( num) => ( return num *2 )) .filterBy (( val ) => return val > 15 )) ;

Let arr1 = arr.map((num) => num*2). Filter (( val) => val > 15);

Let arr1 = arr.map((num) => ( num *2)).filterBy((val) => ( val >15 ));

A developer is creating a simple webpage with a button. When a user clicks this button for the first time, a message is displayed.The developer wrote the JavaScript code below, but something is missing. The message gets displayed every time a user clicks the button, instead of just the first time.01 function listen(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

On line 04, use button.removeEventListener(' click" , listen);

On line 06, add an option called once to button.addEventListener().

On line 02, use event.first to test if it is the first execution.

On line 04, use event.stopPropagation ( ),

On line 04, use button.removeEventListener(' click" , listen);

On line 06, add an option called once to button.addEventListener().

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 events and callbacks to start the servers Which code should be inserted at the line 03 to set up an event and start the web server ?

server.on(' connect ' , ( port) => { console.log('Listening on ' , port) ;})

console.log( 'Listening on ', port) ;

A developer wants to iterate through an array of objects and count the objects and count the 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?

Const sum = curr.name.startsWith('N') ? 1: 0;Return acc +sum

Const sum = curr.startsWith('N') ? 1: 0;Return acc +sum

Const sum = curr.name.startsWith('N') ? 1: 0;Return acc +sum

Const sum = curr.startsWIth('N') ? 1: 0;Return curr+ sum

Const sum = curr.name.startsWIth('N') ? 1: 0;Return curr+ sum

A developer creates a class that represents a blog post based on the requirement that a Post should have a body author and view count.The Code shown Below:Class Post {// 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 to be set to a new instanceof a Post with the three attributes correctly populated?

constructor (body, author, viewCount) {

super (body, author, viewCount) {

Function Post (body, author, viewCount) {

constructor (body, author, viewCount) {

Which three options show valid methods for creating a fat arrow function?Choose 3 answers

x => ( console.log(' executed ') ; )

(x,y,z) => ( console.log(' executed ') ;)

x => ( console.log(' executed ') ; )

[ ] => ( console.log(' executed ') ;)

( ) => ( console.log(' executed ') ;)

X,y,z => ( console.log(' executed ') ;)

(x,y,z) => ( console.log(' executed ') ;)

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 about recordId.Which two options could a developer insert at the placeholder in line 02 to achieve this?Choose 2 answers

'Update' , ( recordId : '123abc'(

'Update' , {Details : { recordId : '123abc'}}

'Update' , ( recordId : '123abc'(

{ type : 'update', recordId : '123abc' }

'Update' , {Details : { recordId : '123abc'}}

A developer is required to write a function that calculates the sum of elements in an array but is getting undefined every time the code is executed. The developer needs to find what is missing in the code below.Const sumFunction = arr => {Return arr.reduce((result, current) => {//Result += current;//), 10););Which option makes the code work as expected?

Replace line 05 with return result;

Replace line 02 with return arr.map(( result, current) => (

Replace line 04 with result = result +current;

Replace line 03 with if(arr.length == 0 ) ( return 0; )

Replace line 05 with return result;

Given code below: setTimeout (() => ( console.log(1);

1000);)).catch(() => ( console.log(4); )); console.log(5); What is logged to the console?

0); console.log(2); New Promise ((resolve, reject )) = > ( setTimeout(() => ( reject(console.log(3));

1000);)).catch(() => ( console.log(4); )); console.log(5); What is logged to the console?

Which statement accurately describes the behaviour of the async/ await keyworks ?

The associated function will always return a promise

The associated class contains some asynchronous functions.

The associated function will always return a promise

The associated function can only be called via asynchronous methods

The associated sometimes returns a promise.

Refer to the code below:Async funct on functionUnderTest(isOK) {If (isOK) return 'OK' ;Throw new Error('not OK');)Which assertion accurately tests the above code?

Console.assert (await functionUnderTest(true), 'OK')

Console.assert (await functionUnderTest(true), ' OK ')

Console.assert (await functionUnderTest(true), ' not OK ')

Console.assert (await functionUnderTest(true), 'OK')

A developer creates a simple webpage with an input field. When a user enters text in the input field and clicks the button, the actual value of the field must be displayed in the console.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 make this code work as expected?

Replace line 04 with console.log(input .value);

Replace line 03 with const input = document.getElementByName('input');

Replace line 02 with button.addEventListener("onclick", function() {

Replace line 02 with button.addCallback("click", function() {

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 execute npm install.Which two reasons could be possible explanations for this?Choose 2 answers

The developer added the dependency as a dev dependency, andNODE_ENVIs set to production.

The developer missed the option --save when adding the dependency.

The developer missed the option --add when adding the dependency.

The developer added the dependency as a dev dependency, andNODE_ENVIs set to production.

The developer missed the option --save when adding the dependency.

A developer is asked to fix some bugs reported by users. To do that, the developer adds a breakpoint for debugging.Function Car (maxSpeed, color){This.maxspeed =masSpeed;This.color = color;Let carSpeed = document.getElementById(' CarSpeed');Debugger;Let fourWheels =new Car (carSpeed.value, 'red');When the code execution stops at the breakpoint on line 06, which two types of information are available in the browser console ?Choose 2 answers:

The style, event listeners and other attributes applied to the carSpeed DOM element

The information stored in the window.localStorage property

The values of the carSpeed and fourWheels variables

A variable displaying the number of instances created for the Car Object.

The style, event listeners and other attributes applied to the carSpeed DOM element

The information stored in the window.localStorage property

At Universal Containers, every team has its own way of copying JavaScript objects. The code Snippet shows an implementation from one team:Function Person() { this.firstName = "John"; this.lastName = 'Doe'; This.name =() => ( console.log('Hello $(this.firstName) $(this.firstName)'); )} Const john = new Person (); Const dan = JSON.parse(JSON.stringify(john)); dan.firstName='Dan'; dan.name(); What is the Output of the code execution?

TypeError: dan.name is not a function

TypeError: Assignment to constant variable.

Refer to the code below:Let textValue = '1984';Which code assignment shows a correct way to convert this string to an integer?

let numberValue = Number(textValue);

Let numberValue = (Number)textValue;

Let numberValue = textValue.toInteger();

Let numberValue = Integer(textValue);

Given HTML below:<div><div id ="row-uc"> Universal Container</div><div id ="row-aa">Applied Shipping</div><div id ="row-bt"> Burlington Textiles </div></div>Which statement adds the priority = account CSS class to the universal Containers row ?

Document .queryElementById('row-uc').addclass('priority-account');

Document .querySelector('#row-uc').classes.push('priority-account');

Document .queryElementById('row-uc').addclass('priority-account');

Document .querySelector('#row-uc').classList.add('priority-account');

Document .querySelectorALL('#row-uc').classList.add('priority-account');

Refer to the code below: const addBy = ? const addByEight =addBy(8); const sum = addBYEight(50); Which two functions can replace line 01 and return 58 to sum?Choose 2 answers

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

const addBY = (num1) => (num2) => num1 + num2;

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

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

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

const addBY = (num1) => (num2) => num1 + num2;

Salesforce Certified JavaScript Developer I Practice Test 1

Question 1 / 40

Refer to the code below:

01 const exec = (item, delay) =>{

02 new Promise(resolve => setTimeout( () => resolve(item), delay)),

03 async function runParallel() {

04 Const (result1, result2, result3) = await Promise.all{

05 [exec ('x', '100') , exec('y', 500), exec('z', '100')]

06 );

07 return `parallel is done: $(result1) $(result2)$(result3)`;

08 }

}}

Which two statements correctly execute the runParallel () function?

Choose 2 answers

Async runParallel () .then(data);

runParallel ( ). done(function(data){ return data;});

runParallel () .then(data);

runParallel () .then(function(data) return data

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Salesforce Certified JavaScript Developer I Practice Test 1

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Salesforce Certified JavaScript Developer I Practice Tests

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