Salesforce JavaScript Developer I Updated Questions Available

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Salesforce JavaScript Developer I updated questions are available, which are good material in your preparation. All the updated JavaScript Developer I questions and answers can help you save much time and energy. Free updated Salesforce JavaScript Developer I exam questions are below.

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1. Given the following code:

document.body.addEventListener(‘ click ’, (event) => {

if (/* CODE REPLACEMENT HERE */) {

console.log(‘button clicked!’);

)

});

Which replacement for the conditional statement on line 02 allows a developer to correctly determine that a button on page is clicked?

Event.clicked

e.nodeTarget ==this

event.target.nodeName == ‘BUTTON’

button.addEventListener(‘click’)

2. Refer to the code below:

new Promise((resolve, reject) => {

const fraction = Math.random();

if( fraction >0.5) reject("fraction > 0.5, " + fraction);

resolve(fraction);

})

.then(() =>console.log("resolved"))

.catch((error) => console.error(error))

.finally(() => console.log(" when am I called?"));

When does Promise.finally on line 08 get called?

When rejected

When resolved and settled

WHen resolved

When resolved or rejected

3. Refer to the following code:

01 function Tiger(){

02 this.Type = ‘Cat’;

03 this.size = ‘large’;

4 }

5

06 let tony = new Tiger();

07 tony.roar = () =>{

08 console.log(‘They’re great1’);

9 };

10

11 function Lion(){

12 this.type = ‘Cat’;

13 this.size = ‘large’;

14 }

15

16 let leo = new Lion();

17 //Insert code here

18 leo.roar();

Which two statements could be inserted at line 17 to enable the function call on line 18? Choose 2 answers.

Leo.roar = () => { console.log(‘They’re pretty good:’); };

Object.assign(leo,Tiger);

Object.assign(leo,tony);

Leo.prototype.roar = () => { console.log(‘They’re pretty good:’); };

4. Consider type coercion, what does the following expression evaluate to?

True + 3 + ‘100’ + null

104

4100

‘3100null’

‘4100null’

5. Refer to the code below:

Const pi = 3.1415326,

What is the data type of pi?

Double

Number

Decimal

Float

6. bar, awesome is a popular JavaScript module. the versions publish to npm are:

Teams at Universal Containers use this module in a number of projects. A particular project has the package, json definition below.

A developer runs this command: npm install.

Which version of bar .awesome is installed?

1.3.1

1.3.5

The command fails, because version 130 is not found

1.4.0

7. Which statement parses successfully?

JSO

parse (""foo"');

JSO

parse (""foo'");

JSO

parse ("foo");

JSO

parse ("foo");

8. A developer wrote the following code to test a sum3 function that takes in an array of numbers and returns the sum of the first three numbers in the array, and the test passes.

A different developer made changes to the behavior of sum3 to instead sum only the first two numbers present in the array.

Which two results occur when running this test on the updated sum3 function? Choose 2 answers

The line 05 assertion passes.

The line 02 assertion passes.

The line 02 assertion fails.

The line 05 assertion fails.

9. Refer to the code below:

Let car1 = new Promise((_ , reject) =>

setTimeout(reject, 2000, “car 1 crashed in” =>

Let car2 =new Promise(resolve => setTimeout(resolve, 1500, “car 2 completed”)

Let car3 =new Promise(resolve => setTimeout(resolve, 3000, “car 3 completed”)

Promise.race(( car1, car2, car3))

.then (value => (

Let result = ‘$(value) the race.’;)}

.catch(arr => {

console.log(“Race is cancelled.”, err);

});

What is the value of result when Promise.race executes?

Car 3 completes the race

Car 2 completed the race.

Car 1 crashed in the race.

Race is cancelled.

10. Given two expressions var1 and var2 .

What are two valid ways to return the logical AND of the two expressions and ensure it is data type Boolean? Choose 2 answers:

Boolean(var1 && var2)

var1 && var2

var1.toBoolean() && var2toBoolean()

Boolean(var1) && Boolean(var2)

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11. A developer has an ErrorHandler module that contains multiple functions.

What kind of export be leverages so that multiple functions can be used?

Named

All

Multi

Default

12. Refer to the code below:

Line 05 causes an error.

What are the values of greeting and salutation once code completes?

Greeting is Hello and salutation is Hello, Hello.

Greeting is Goodbye and salutation is Hello, Hello.

Greeting is Goodbye and salutation is I say Hello.

Greeting is Hello and salutation is I say hello.

13. Given the code below:

const delay = sync delay => {

Return new Promise((resolve, reject) => {

setTimeout (resolve, delay);});};

const callDelay =async () =>{

const yup =await delay(1000);

console.log(1);

What is logged to the console?

1 2 3

1 3 2

2 1 3

2 3 1

14. myArraym can have one level, two levels, or more levels.

Which statement flattens myArray when it can be arbitrarily nested?

myArray. reduce ((prev, curr) => prev.concat(curr) [ ]);

myArray. join (","). split (",");

[ ] .concat {. . .myArray) ;

myArray.flat(Infinity);

15. Refer to the code snippet below:

Let array = [1, 2, 3, 4, 4, 5, 4, 4];

For (let i =0; i < array.length; i++){

if (array[i] === 4) {

array.splice(i, 1);

}

}

What is the value of the array after the code executes?

[1, 2, 3, 4, 5, 4, 4]

[1, 2, 3, 4, 4, 5, 4]

[1, 2, 3, 4, 5, 4]

[1, 2, 3, 5]

16. Refer to the code below:

Let str = ‘javascript’;

Str[0] = ‘J’;

Str[4] = ’S’;

After changing the string index values, the value of str is ‘javascript’ .

What is the reason for this value:

Non-primitive values are mutable.

Non-primitive values are immutable.

Primitive values are mutable.

Primitive values are immutable.

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

x => ( console.log(‘ executed ’) ; )

[ ] => ( console.log(‘ executed ’) 😉

( ) => ( console.log(‘ executed ’) 😉

X,y,z => ( console.log(‘ executed ’) 😉

(x,y,z) => ( console.log(‘ executed ’) 😉

18. The developer wants to test the array shown:

const arr = Array(5).fill(0)

Which two tests are the most accurate for this array? Choose 2 answers:

console.assert( arr.length === 5 );

arr.forEach(elem => console.assert(elem === 0)) ;

console.assert(arr[0] === 0 && arr[ arr.length] === 0);

console.assert (arr.length >0);

19. Which two console logs outputs NaN? Choose 2 answers

console.log(10/ Number(‘5’));

console.log(parseInt(‘two’));

console.log(10/ ‘’five);

console.log(10/0);

20. Which statement phrases successfully?

JSO

parse ( ‘ foo ’ );

JSO

parse ( “ foo ” );

JSO

parse( “ ‘ foo ’ ” );

JSO

parse(‘ “ foo ” ’);

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21. Refer to code below:

Let a =’a’;

Let b;

// b = a; console.log(b);

What is displayed when the code executes?

Reference Error: b is not defined

Undefined

Null

22. A developer wants to leverage a module to print a price in pretty format, and has imported a method as shown below:

Import printPrice from ‘/path/PricePrettyPrint.js’;

Based on the code, what must be true about the printPrice function of the PricePrettyPrint module for this import to work?

printPrice must be be a named export

printPrice must be an all export

printPrice must be the default export

printPrice must be a multi exportc

23. Refer to the code below:

console.log(‘’start);

Promise.resolve(‘Success’) .then(function(value){

console.log(‘Success’);

});

console.log(‘End’);

What is the output after the code executes successfully?

End Start Success

Start Success End

Start End Success

Success Start End

24. Refer to the code below:

Let inArray =[ [ 1, 2 ] , [ 3, 4, 5 ] ];

Which two statements result in the array [1, 2, 3, 4, 5]? Choose 2 answers

[ ]. Concat.apply ([ ], inArray);

[ ]. Concat (... inArray);

[ ]. concat.apply(inArray, [ ]);

[ ]. concat ( [ ….inArray ] );

25. is below:

<input type=”file” onchange=”previewFile()”> <img src=”” height=”200” alt=”Image Preview…”/> The JavaScript portion is:

01 function previewFile(){

02 const preview = document.querySelector(‘img’);

03 const file = document.querySelector(‘input[type=file]’).files[0];

04 //line 4 code

05 reader.addEventListener(“load”, () => {

06 preview.src = reader.result;

07 },false);

08 //line 8 code

09 }

In lines 04 and 08, which code allows the user to select an image from their local computer, and to display the image in the browser?

04 const reader = new File(); 08 if (file) UR

createObjectURL(file);

04 const reader = new FileReader(); 08 if (file) UR

createObjectURL(file);

04 const reader = new File(); 08 if (file) reader.readAsDataURL(file);

04 const reader = new FileReader(); 08 if (file) reader.readAsDataURL(file);

26. Refer to HTML below:

<div id =”main”>

<div id = “ card-00”>This card is smaller.</div>

<div id = “card-01”>The width and height of this card is determined by its

contents.</div>

</div>

Which expression outputs the screen width of the element with the ID card-01?

document.getElementById(‘ card-01 ’).getBoundingClientRest().width

document.getElementById(‘ card-01 ’).style.width

document.getElementById(‘ card-01 ’).width

document.getElementById(‘ card-01 ’).innerHTM

lenght*e

27. A developer creates an object where its properties should be immutable and prevent

properties from being added or modified.

Which method should be used to execute this business requirement?

Object.const()

Object.eval()

Object.lock()

Object.freeze()

28. Refer to the code below:

Which value can a developer expect when referencing country,capital,city String?

'London'

undefined

An error

'NaN'

29. Refer of the string below:

Const str = ‘sa;esforce’=;

Which two statement result in the word 'Sale'? Choose 2 answers

str, substring (0,5) ;

str, substr(0,5) ;

str, substring(1,5) ;

str, substr(1,5) ;

30. Which three browser specific APIs are available for developers to persist data between page loads? Choose 3 answers

IIFEs

indexedDB

Global variables

localStorage.

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31. A developer wrote a fizzbuzz function that when passed in a number, returns the following:

‘Fizz’ if the number is divisible by 3.

‘Buzz’ if the number is divisible by 5.

‘Fizzbuzz’ if the number is divisible by both 3 and 5.

Empty string if the number is divisible by neither 3 or 5.

Which two test cases will properly test scenarios for the fizzbuzz function? Choose 2 answers

let res = fizzbuzz(5); console.assert ( res === ‘ ’ );

let res = fizzbuzz(15); console.assert ( res === ‘ fizzbuzz ’ )

let res = fizzbuzz(Infinity); console.assert ( res === ‘ ’ )

let res = fizzbuzz(3); console.assert ( res === ‘ buzz ’ )

32. A test has a dependency on database.query. During the test the dependency is replaced with an object called database with the method, query, that returns an array. The developer needs to verify how many times the method was called and the arguments used each time.

Which two test approaches describe the requirement? Choose 2 answers

Integration

Black box

White box

Mocking

33. The developer has a function that prints “Hello” to an input name. To test this, the developer created a function that returns “World”. However the following snippet does not print “Hello World”.

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

Change line 7 to ) () ;

Change line 2 to console.log(‘Hello’ , name() );

Change line 9 to sayHello(world) ();

Change line 5 to function world ( ) {

34. Refer to code below:

Let productSKU = ‘8675309’ ;

A developer has a requirement to generate SKU numbers that are always 19 characters lon, starting with ‘sku’, and padded with zeros.

Which statement assigns the values sku 0000000008675309?

productSKU = productSK

padStart (19. ‘0’).padstart(‘sku’);

productSKU = productSK

padEnd (16. ‘0’).padstart(‘sku’);

productSKU = productSK

padEnd (16. ‘0’).padstart(19, ‘sku’);

productSKU = productSK

padStart (16. ‘0’).padstart(19, ‘sku’);

35. Refer to HTML below:

<p> The current status of an Order: <span id =”status”> In Progress </span> </p>.

Which JavaScript statement changes the text ‘In Progress’ to ‘Completed’?

document.getElementById(“status”).Value = ’Completed’ ;

document.getElementById(“#status”).innerHTML = ’Completed’ ;

document.getElementById(“status”).innerHTML = ’Completed’ ;

document.getElementById(“.status”).innerHTML = ’Completed’ ;

36. Universal Containers (UC) notices that its application that allows users to search for accounts makes a network request each time a key is pressed. This results in too many requests for the server to handle.

Address this problem, UC decides to implement a debounce function on string change handler.

What are three key steps to implement this debounce function? Choose 3 answers:

If there is an existing setTimeout and the search string change, allow the existing setTimeout to finish, and do not enqueue a new setTimeout.

When the search string changes, enqueue the request within a setTimeout.

Ensure that the network request has the property debounce set to true.

If there is an existing setTimeout and the search string changes, cancel the existing setTimeout using the persisted timerId and replace it with a new setTimeout.

Store the timeId of the setTimeout last enqueued by the search string change handle.

37. The developer wants to test this code:

Const toNumber =(strOrNum) => strOrNum;

Which two tests are most accurate for this code? Choose 2 answers

console.assert(toNumber(‘2’) === 2);

console.assert(Number.isNaN(toNumber()));

console.assert(toNumber(‘-3’) < 0);

console.assert(toNumber () === NaN);

38. Refer to the code below:

<html lang=”en”>

<table onclick=”console.log(Table log’);”>

<tr id=”row1”>

<td>Click me!</td>

</tr>

<table>

<script>

function printMessage(event) {

console.log(‘Row log’);

}

Let elem = document.getElementById(‘row1’);

elem.addEventListener(‘click’, printMessage, false);

</script>

</html>

Which code change should be made for the console to log only Row log when ‘Click me! ’ is clicked?

Add.event.stopPropagation(); to window.onLoad event handler.

Add event.stopPropagation(); to printMessage function.

Add event.removeEventListener(); to window.onLoad event handler.

Add event.removeEventListener(); toprintMessage function.

39. What are two unique features of functions defined with a fat arrow as compared to normal function definition? Choose 2 answers

The function generated its own this making it useful for separating the function’s scope from its enclosing scope.

The function receives an argument that is always in scope, called parent This, which is the enclosing lexical scope.

If the function has a single expression in the function body, the expression will be evaluated and implicit returned.

The function uses the this from the enclosing scope.

40. Refer to the following code:

function test (val) {

If (val === undefined) {

return ‘Undefined values!’ ;

}

if (val === null) {

return ‘Null value! ’;

}

return val;

}

Let x;

test(x);

What is returned by the function call on line 13?

Undefined

Line 13 throws an error.

‘Undefined values!’

‘Null value!’

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41. 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?

Console.assert (await functionUnderTest(true), ‘ OK ’)

Console.assert (await functionUnderTest(true), ‘ not OK ’)

Console.assert (await functionUnderTest(true), ‘OK’)

42. 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(0)) == 0);

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

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

43. Given code below:

setTimeout (() => (

console.log(1);

). 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?

2 1 4 3 5

2 5 1 3 4

1 2 4 3 5

1 2 5 3 4

44. 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)`;

8 }

}

}

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

45. In the browser, the window object is often used to assign variables that require the broadest scope in an application Node.js application does not have access to the window object by default.

Which two methods are used to address this? Choose 2 answers

Use the document object instead of the window object.

Assign variables to the global object.

Create a new window object in the root file.

Assign variables to module.exports and require them as needed.

46. developer has a web server running with Node.js. The command to start the web server is node server,js. The web server started having latency issues. Instead of a one second turn around for web requests, the developer now sees a five second turnaround,

Which command can the web developer run to see what the module is doing during the latency period?

DEBUG = http, https node server.js

NODE_DEBUG =http, https node server.js

DEBUG =true node server.js

NODE_DEBUG =true node server.js

47. Refer to the code below:

After running this code, which result is displayed on the console?

> true > false

> 5 >undefined

> 5 > -1

> 5 > 0

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

It is required by the application in production.

It is only needed for local development and testing.

Other required packages depend on it for development.

It should be bundled when the package is published.

49. A developer wants to define a function log to be used a few times on a single-file JavaScript script.

01 // Line 1 replacement

02 console.log('"LOG:', logInput);

03 }

Which two options can correctly replace line 01 and declare the function for use? Choose 2 answers

function leg(logInput) {

const log(loginInput) {

const log = (logInput) => {

function log = (logInput) {

50. 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 02

02 //missing line 03

04 ). 0);

Which missing lines 02 and 03 return the correct count?

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

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51. Refer to the code below:

let sayHello = () => {

console.log (‘Hello, world!’);

};

Which code executes sayHello once, two minutes from now?

setTimeout(sayHello, 12000);

setInterval(sayHello, 12000);

setTimeout(sayHello(), 12000);

delay(sayHello, 12000);

52. Which three statements are true about promises? Choose 3 answers

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.

Salesforce JavaScript Developer I Updated Questions Available

Salesforce JavaScript Developer I Updated Questions Available

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