Course 2025 JavaScript-Developer-I Test Prep Training Practice Exam Download
JavaScript-Developer-I Exam Info and Free Practice Test Professional Quiz Study Materials
Salesforce JavaScript-Developer-I Exam is an essential certification for anyone who plans to develop applications on the Salesforce platform using JavaScript. It demonstrates a person’s proficiency in developing secure and scalable applications that can be customized to meet specific business needs. By passing JavaScript-Developer-I exam, candidates can enhance their career prospects, increase job opportunities, and develop a strong foundation in Salesforce development.
Salesforce JavaScript-Developer-I is a certification exam designed for professionals who want to demonstrate their expertise in using JavaScript and related technologies to develop custom applications on the Salesforce platform. JavaScript-Developer-I exam measures the candidate's knowledge of the fundamental concepts of JavaScript, including data types, control structures, functions, arrays, and objects, as well as their ability to apply this knowledge to solve real-world programming problems.
NEW QUESTION # 91
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?
- A. Const sum = curr.name.startsWith('N') ? 1: 0;
Return acc +sum - B. Const sum = curr.name.startsWIth('N') ? 1: 0;
Return curr+ sum - C. Const sum = curr.startsWith('N') ? 1: 0;
Return acc +sum - D. Const sum = curr.startsWIth('N') ? 1: 0;
Return curr+ sum
Answer: A
NEW QUESTION # 92
Which function should a developer use to repeatedly execute code at a fixed time interval?
- A. setPeriod
- B. setInterim
- C. setTimeout
- D. setInterval
Answer: D
NEW QUESTION # 93
developer wants to use a module named universalContainersLib and them call functions from it.
How should a developer import every function from the module and then call the functions foo and bar ?
- A. import (foo, bar) from '/path/universalContainersLib.js';
foo();
bar(); - B. import * ad lib from '/path/universalContainersLib.js';
lib.foo();
lib.bar(); - C. import all from '/path/universalContaineraLib.js';
universalContainersLib.foo();
universalContainersLib.bar(); - D. import * from '/path/universalContaineraLib.js';
universalContainersLib.foo();
universalContainersLib.bar();
Answer: B
NEW QUESTION # 94
Refer to the code below:
01 const exec = (item, delay) =>{
02newPromise(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
- A. Async runParallel () .then(data);
- B. runParallel () .then(data);
- C. runParallel ( ). done(function(data){return data;});
- D. runParallel () .then(function(data)return data
Answer: C,D
NEW QUESTION # 95
Refer to the following array:
Let arr = [1, 2, 3, 4, 5];
Which three options result in x evaluating as [1, 2]?
Choose 3 answer
- A. let x arr.filter((a) => (return a <= 2 });
- B. let x =arr.splice(0, 2);
- C. let x = arr. slice (2);
- D. let x = arr. slice (0, 2);
- E. let x = arr.filter ((a) => 2 }) ;
Answer: A,B,D
NEW QUESTION # 96
Refer to the following code:
Let sampletext = 'The quick brown fox Jumps';
A developer need to determine if a certain substring is part of a string.
Which three expressions return true for the give substring? Choose 3 answers
- A. sampleText.substing ('fox');
- B. sampleText.includes (fox' , 3);
- C. sampleText.includes (quick', 4);
- D. sampleText.indexof ('quick') 1== -1;
- E. sampleText.inclides (fox');
Answer: B
NEW QUESTION # 97
Which code change should be done for the console to log the following when 'Click me!' is clicked'
> Row log
> Table log
- A. Remove lines 13 and 14
- B. Change line 14 to elem.addEventListener ('click', printMessage, true);
- C. Change line 10 to event.stopPropagation (false) ;
- D. Remove line 10
Answer: C
NEW QUESTION # 98
Given the requirement to refactor the code above to JavaScript class format, which class definition is correct?
A)
B)
C)
D)
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Answer: A
NEW QUESTION # 99
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
- A. 'Update' , (
recordId : '123abc'
( - B. 'Update' , '123abc'
- C. { type : 'update', recordId : '123abc' }
- D. 'Update' , {
Details : {
recordId : '123abc'
}
}
Answer: A,D
NEW QUESTION # 100
Given the expressions var1 and var2, what are two valid ways to return the concatenation of the two expressions and ensure it is string? Choose 2 answers
- A. String (var1) .concat (var2)
- B. var1 + var2
- C. var1.toString ( ) var2.toString ( )
- D. string.concat (var1 +var2)
Answer: C,D
NEW QUESTION # 101
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. leo.roar = () => { console.log('They\'re pretty good!'); );
- C. Object.assign (leo. Tiger);
- D. Object.assign (leo, tony);
Answer: B,D
NEW QUESTION # 102
Refer to code below:
Const objBook = {
Title: 'Javascript',
};
Object.preventExtensions(objBook);
Const newObjBook = objBook;
newObjectBook.author = 'Robert';
What are the values of objBook and newObjBook respectively ?
- A. {author: "Robert", title: "javaScript}
Undefined - B. [title: "javaScript"] [title: "javaScript"]
- C. {author: "Robert"}
{author: "Robert", title: "javaScript} - D. {author: "Robert", title: "javaScript}
{author: "Robert", title: "javaScript}
Answer: B
NEW QUESTION # 103
Universal Containers recently its new landing page to host crowd-function campaign. The page uses an external library to display some third-party ads. Once the page is fully loaded, It creates more than 50 new HTML items placed randomly inside the DOM, like the one in the code below.
All the elements included the same ad-library-item class. They are hidden by default, and they are randomly displayed while the user navigation through the page.
Tired of all the ads, what can the developer do to temporarily and quickly remove them?
- A. Use the DOM inspector to remove all the elements containing the call ad-library -item.
- B. Use the browser console to execute a script that prevents the load event to be fired.
- C. Use the DOM inspector to prevent the load event to be fired.
- D. Use the browser console to execute a script that removes all the elements containing the class ad-library-item.
Answer: D
NEW QUESTION # 104
Given the following code:
What is the output of line 02?
- A. 'object"
- B. "x-
- C. "undefined" 0
- D. "null"
Answer: A
NEW QUESTION # 105
A developer is debugging a web server that uses Node.js. The server hits a runtime error every third request to an important endpoint on the web server.
The developer added a break point to the start script, that is at index, js at the root of the server's source code. The developer wants to make use of Chrome DevTools to debug.
Which command can be run to access DevTools and make sure the breakpoint is hit?
- A. Node --inspect -brk index , js
- B. Node -- inspect index ,js
- C. Node inspect index , js
- D. Node -I index , js
Answer: B
NEW QUESTION # 106
Refer to the following code block:
class Animal{
constructor(name){
this.name = name;
}
makeSound(){
console.log(`${this.name} is making a sound.`)
}
}
class Dog extends Animal{
constructor(name){
super(name)
this.name = name;
}
makeSound(){
console.log(`${this.name} is barking.`)
}
}
let myDog = new Dog('Puppy');
myDog.makeSound();
What is the console output?
- A. Puppy is barking
Answer: A
NEW QUESTION # 107
Refer to the following object.
How can a developer access the fullName property for dog?
- A. Dog, get, fullName
- B. Dog.fullName
- C. Dog.fullName ( )
- D. Dog, function, fullName
Answer: B
NEW QUESTION # 108
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?
- A. Replace line 03 with const input = document.getElementByName('input');
- B. Replace line 02 with button.addEventListener("onclick", function() {
- C. Replace line 04 with console.log(input .value);
- D. Replace line 02 with button.addCallback("click", function() {
Answer: C
NEW QUESTION # 109
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 Hello, Hello.
- B. Greeting is Goodbye and salutation is I say Hello.
- C. Greeting is Goodbye and salutation is Hello, Hello.
- D. Greeting is Hello and salutation is I say hello.
Answer: A
NEW QUESTION # 110
A developer writes the code below to return a message to a user attempting to register a new username. If the username is available, a variable named nag is declared and assigned a value on line 03.
What is the value of msg when getAvailableabilityMessage ("newUserName") is executed and get Availability ("newUserName") returns true?
- A. undefined
- B. "msg is not defined"
- C. "newUserName"
- D. "User-name available"
Answer: D
NEW QUESTION # 111
A team that works on a big project uses npm to deal with the project's dependencies.
A developer added a dependency to manipulated dates and pushed the updates to the remote repository. The rest of the team complains that the dependency does not get download when they execute npm install.
Which two reason could be possible explanation for this?
- A. The developer added the dependency as a dev dependency, and NODK_ENV is set to production.
- B. The developer missed the option - add when adding the dependency.
- C. The developer missed the option -ssve when adding the dependency.
- D. The developer added the dependency as a dev dependency, and NOOK_ENV is set to production.
Answer: A,C,D
NEW QUESTION # 112
Refer to the following code:
Which statement should be added to line 09 for the code to display 'The boat has a capacity of 10 people?
- A. ship.size size;
- B. this.size = size;
- C. super (size);
- D. super.size = size;
Answer: B
NEW QUESTION # 113
A developer writes the code below to return a message to a user attempting to register a new username. If the username is available, a variable named nag is declared and assigned a value on line 03.
What is the value of msg when getAvailableabilityMessage ("newUserName") is executed and get Availability ("newUserName") returns true?
- A. undefined
- B. "msg is not defined"
- C. "newUserName"
- D. "User-name available"
Answer: D
NEW QUESTION # 114
A developer wants to literate through an array of objects and count the objects whose property value, name, start with the letter N. const arrobj - [{''name ''t ''Zach''}, { ''name t Kate'') , ( ''name Alice'') < ( ''name'' t ''Bob'') , (''name'' t ''Nathan) , (''name'' t ''Nathandle1'')] Refer to the code snippet below:
Which missing lines 02 and 03 return the correct count?
- A. Conset sun + curr. StartsWith ('N') 7 1 : 1;
Return acc + sum ; - B. Comst sum = curr. name startsWith ('N') 7 1 : 0;
Return curr + sum; - C. Const sum = curr. name startsWith ('N') 7 1 : 0;
Return curr + sum; - D. Comst sum = curr. Name startsWith ('N') 7 1 : 0
Return acc + sum;
Answer: D
NEW QUESTION # 115
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