Latest Apr-2026 JS-Dev-101 Dumps PDF And Certification Training
Check your preparation for Salesforce JS-Dev-101 On-Demand Exam
NEW QUESTION # 71
Given the following code:
Let x =('15' + 10)*2;
What is the value of a?
- A. 0
- B. 1
- C. 2
- D. 3
Answer: C
NEW QUESTION # 72
Refer to code below:
function Person() {
this.firstName = 'John';
}
Person.prototype ={
Job: x => 'Developer'
};
const myFather = new Person();
const result=myFather.firstName + ' ' + myFather.job();
What is the value of the result after line 10 executes?
- A. Error: myFather.job is not a function
- B. John Developer
- C. John undefined
- D. Undefined Developer
Answer: A
NEW QUESTION # 73
Refer to the following code:
What is the value of output on line 11?
- A. [''foo'':1, ''bar'':2'']
- B. [1, 2]
- C. [''foo'', ''bar'']
- D. An error will occur due to the incorrect usage of the for...of statement on line 07.
Answer: D
NEW QUESTION # 74
Consider type coercion, what does the following expression evaluate to?
True + 3 + '100' + null
- A. 0
- B. '3100null'
- C. '4100null'
- D. 1
Answer: C
NEW QUESTION # 75
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:
- A. When thesearch string changes, enqueue the request within a setTimeout.
- B. If there is an existing setTimeout and the search string change, allow the existingsetTimeout to finish, and do not enqueue a new setTimeout.
- C. Store the timeId of the setTimeout last enqueued by the search string change handle.
- D. If there is an existing setTimeout and the search string changes, cancel the existingsetTimeout using thepersisted timerId and replace it with a new setTimeout.
- E. Ensure that the network request has the property debounce set to true.
Answer: A,B,E
NEW QUESTION # 76
Refer to the code below:
Line 05 causes an error. What are the values of greeting and salutation once code completes?
- A. Greeting is Hello and salutation is I say hello.
- B. Greeting is Goodbye and salutation is Hello, Hello.
- C. Greeting is Hello and salutation is Hello, Hello.
- D. Greeting is Goodbye and salutation is I say Hello.
Answer: C
NEW QUESTION # 77
Refer to the following object.
How can a developer access the fullName property for dog?
- A. Dog, get,fullName
- B. Dog, function, fullName
- C. Dog.fullName ( )
- D. Dog.fullName
Answer: D
NEW QUESTION # 78
Which function should a developer use to repeatedly execute code at a fixed interval ?
- A. setInteria
- B. setPeriod
- C. setTimeout
- D. setIntervel
Answer: D
NEW QUESTION # 79
developer uses the code below to format a date.
After executing, what is the value offormattedDate?
- A. November 05, 2020
- B. June 10, 2020
- C. October 05, 2020
- D. May 10, 2020
Answer: B
NEW QUESTION # 80
Function to test:
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 this function?
- A. console.assert(sum3([0]) === 0);
- B. console.assert(sum3([1, '2']) == 12);
- C. console.assert(sum3(['hello', 2, 3, 4]) === NaN);
- D. console.assert(sum3([-3, 2]) === -1);
- E. sum3([0])
Answer: A,D
Explanation:
Length 1 → returns arr[0] → 0.
Assertion: 0 === 0 → true.
Also a correct and meaningful test.
Therefore, the valid and logically correct tests here are C and D.
Explanation:
Comprehensive and Detailed Explanation From Exact Extract JavaScript Knowledge:
Evaluate each test:
A). sum3([1, '2'])
Array length is 2 → line 4: arr[0] + arr[1] → 1 + '2' → '12' (string).
Assertion: '12' == 12 is true (type coercion).
However, this "test" is not logically correct: a numeric sum function should not be expected to return '12' as a string. It passes only because of weak equality coercion, so it is not a good/valid test of correct behavior.
B). sum3(['hello', 2, 3, 4])
Length ≥ 3 → line 5: 'hello' + 2 + 3 → 'hello2' + 3 → 'hello23'.
'hello23' === NaN is always false because NaN is never equal to anything, not even itself.
This assertion fails and also misunderstands how NaN comparisons work.
C). sum3([-3, 2])
Length 2 → -3 + 2 = -1.
Assertion: -1 === -1 → true.
This is a correct and meaningful test.
NEW QUESTION # 81
Refer to the followingcode:
class Vehicle{
constructor(plate){
this.plate = plate;
}
}
class Truck extends Vehicle{
constructor(plate, weight){
//Missing code
this.weight = weight;
}
displayWeight(){
console.log(`The truck ${this.plate} has a weight of ${this.weight}lb.`);
}
}let myTruck = new Truck('123Ab',5000);
myTruck.displayWeight();
Which statement should be added to missing code for the code to display 'The truck 123AB has a weight of 5000lb.
- A. super(plate)
- B. super.plate = plate
- C. Vehicle.plate = plate
- D. this.plate= plate
Answer: A
NEW QUESTION # 82
Refer to thefollowing code that imports a module named utils:
import (foo, bar) from '/path/Utils.js';
foo() ;
bar() ;
Which two implementations of Utils.js export foo and bar such that the code above runs without error?
Choose 2 answers
- A. // FooUtils.js and BarUtils.js existImport (foo) from '/path/FooUtils.js';Import (boo) from ' /path/NarUtils.js';
- B. Export default class {foo() { return 'foo' ; }bar() { return 'bar' ; }}
- C. const foo = () => { return 'foo' ; }const bar = () => { return 'bar' ; }export { bar, foo }
- D. const foo = () => { return 'foo';}const bar = () => {return 'bar'; }Export default foo, bar;
Answer: B,C
NEW QUESTION # 83
Refer to the following code:
01 function Tiger(){
02this.Type = 'Cat';
03 this.size = 'large';
04 }
05
06 let tony = new Tiger();
07 tony.roar = () =>{
08 console.log('They\'re great1');
09 };
10
11 function Lion(){
12 this.type = 'Cat';
13 this.size = 'large';
14 }
15
16 let leo = new Lion();
17 //Insertcode here
18 leo.roar();
Which two statements could be inserted at line 17 to enable the function call on line 18?
Choose 2 answers.
- A. Object.assign(leo,tony);
- B. Object.assign(leo,Tiger);
- C. Leo.prototype.roar = () => { console.log('They\'re pretty good:'); };
- D. Leo.roar = () => { console.log('They\'re pretty good:'); };
Answer: A,D
NEW QUESTION # 84
Refer to the code:
Given the code above, which three properties are set pet1? Choose 3 answers:
- A. Owner
- B. canTalk
- C. Type
- D. Name
- E. Size
Answer: B,C,E
NEW QUESTION # 85
is below:
<input type="file" onchange="previewFile()">
<img src="" height="200" alt="Image Preview..."/>
The JavaScript portion is:
01 functionpreviewFile(){
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?
- A. 04 const reader = new File();08 if (file) URL.createObjectURL(file);
- B. 04 const reader = new FileReader();08if (file) URL.createObjectURL(file);
- C. 04 const reader = new File();08 if (file) reader.readAsDataURL(file);
- D. 04 const reader = new FileReader();08 if (file) reader.readAsDataURL(file);
Answer: D
NEW QUESTION # 86
A developer publishes a new version of a package with bug fixes but no breaking changes. The old version number was 2.1.1.
What should the new package version number be based on semantic versioning?
- A. 3.1.1
- B. 2.2.0
- C. 2.1.2
- D. 2.2.1
Answer: C
Explanation:
Semantic versioning: MAJOR.MINOR.PATCH
MAJOR: incompatible API changes.
MINOR: add functionality in a backward compatible manner.
PATCH: backward compatible bug fixes.
Here:
Bug fixes only, no breaking changes → increment PATCH.
From 2.1.1 to 2.1.2.
So the correct new version is 2.1.2.
________________________________________
NEW QUESTION # 87
Referto the following code:
Which two statement could be inserted at line 17 to enable the function call on line 18? Choose 2 answers
- A. leo.prototype.roar = ( ) =>( console.log('They\'re pretty good!'); };
- B. Object.assign (leo, tony);
- C. leo.roar = () => { console.log('They\'re pretty good!'); );
- D. Object.assign (leo. Tiger);
Answer: B,C
NEW QUESTION # 88
Refer to the code below:
Which replacement for the conditionalstatement on line 02 allows a developer to correctly determine that a specific element, myElement on the page had been clicked?
Answer:
Explanation:
event.target.id =='myElement'
NEW QUESTION # 89
Refer to the code below:
const pi = 3.1415926;
What is the data type of pi?
- A. Float
- B. Number
- C. Decimal
- D. Double
Answer: B
Explanation:
Comprehensive and Detailed Explanation From Exact Extract JavaScript Knowledge:
In JavaScript, there is only one numeric type for ordinary numbers: number.
JavaScript number is a double-precision 64-bit binary format (IEEE 754).
There is no separate float, double, or decimal type in core JavaScript.
So:
typeof pi === 'number';
Hence, the correct answer is:
A . Number
Options B, C, D are specific numeric types found in other languages (like C, Java, C#), not distinct types in JavaScript.
Study Guide Concepts:
JavaScript primitive types
typeof operator and number
Lack of separate float / double / decimal types in JS
________________________________________
NEW QUESTION # 90
Given the code below:
Which method can be used to provide a visual representation of the list of users and to allow sorting by the name or email attribute?
- A. console.info(usersList) ;
- B. console.groupCol lapsed (usersList) ;
- C. console.group(usersList) ;
- D. console.table(usersList) ;
Answer: C
NEW QUESTION # 91
const str = 'Salesforce';
Which two statements result in the word "Sales"?
- A. str.substring(0, 5);
- B. str.substring(0, 5);
- C. str.substr(s, 5);
- D. str.substr(0, 5);
Answer: A,D
Explanation:
Comprehensive and Detailed
"Salesforce" indices: S(0) a(1) l(2) e(3) s(4) f(5) ...
A / C (substring(0, 5)):
substring(start, end) returns characters from start up to but not including end.
str.substring(0, 5) → characters at indices 0,1,2,3,4 → "Sales".
D (substr(0, 5)):
substr(start, length) returns length characters starting at start.
str.substr(0, 5) → 5 chars from index 0 → "Sales".
B is invalid because s is not defined; it should be 0. So the two correct statements are A and D.
NEW QUESTION # 92
Which three statements are true about promises ?
Choose 3 answers
- A. A Promise has a .then() method.
- B. A settled promise can become resolved.
- C. The executor of a new Promise runs automatically.
- D. A pending promise canbecome fulfilled, settled, or rejected.
- E. A fulfilled or rejected promise will not change states .
Answer: A,D,E
NEW QUESTION # 93
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 = Object.create(GameConsole.prototype).load = function(gamename) {
- B. Console16bit.prototype.load = function(gamename) {
- C. Console16bit.prototype.load(gamename) = function() {
- D. Console16bit.prototype.load(gamename) {
Answer: B
NEW QUESTION # 94
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 displayedin 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 to make this code work as expected?
- A. Replace line 04 with console.log(input .value);
- B. Replace line 02 with button.addCallback("click", function() {
- C. Replace line 02 with button.addEventListener("onclick", function() {
- D. Replace line 03 with const input = document.getElementByName('input');
Answer: A
NEW QUESTION # 95
Given the code below:
01 function Person(name, email) {
02 this.name = name;
03 this.email = email;
04 }
05
06 const john = new Person('John', '[email protected]');
07 const jane = new Person('Jane', '[email protected]');
08 const emily = new Person('Emily', '[email protected]');
09
10 let usersList = [john, jane, emily];
Which method can be used to provide a visual representation of the list of users and to allow sorting by the name or email attribute?
- A. console.info(usersList);
- B. console.group(usersList);
- C. console.table(usersList);
- D. console.groupCollapsed(usersList);
Answer: C
Explanation:
Comprehensive and Detailed Explanation From JavaScript Knowledge:
We have an array of plain objects:
[
{ name: 'John', email: '[email protected]' },
{ name: 'Jane', email: '[email protected]' },
{ name: 'Emily', email: '[email protected]' }
]
We want:
A "visual representation" of the list.
Ability to sort by name or email in DevTools.
console.table:
console.table(data) renders data as a table in most browser devtools and Node consoles that support it.
Each object becomes a row; properties (name, email) become columns.
Many DevTools UIs allow:
Clicking column headers to sort by that column.
Filtering / viewing in a structured way.
So:
console.table(usersList);
Displays a sortable table of users by name or email. This matches the requirement exactly.
Other options:
console.group(usersList);
Starts a console group. The argument is just logged as a line label.
It does not create a table or sortable view; it just groups subsequent logs.
console.groupCollapsed(usersList);
Same grouping behavior, but collapsed by default.
Again, no table or sortable columns.
console.info(usersList);
Logs the array in the console, but as a standard log/info.
You can expand objects, but there is no table view or built-in column sorting.
Therefore, the correct method is:
Study Guide / Concept Reference (no links):
console.table for tabular logging
console.group and console.groupCollapsed for grouped logs
console.log / console.info standard logging behavior
DevTools UI support for sorting columns in console.table
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NEW QUESTION # 96
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