Leading Salesforce Certified JavaScript Developer I JavaScript-Developer-I Training Tools

NEW QUESTION 1
Which three actions can be using the JavaScript browser console? Choose 3 answers:

• A. View and change DOM the page.
• B. Display a report showing the performance of a page.
• C. Run code that is not related to page.
• D. view , change, and debug the JavaScript code of the page.
• E. View and change security cookies.

Answer: ACD

NEW QUESTION 2
Cloud Kicks has a class to represent items for sale in an online store, as shownbelow: Class Item{
constructor (name, price){ this.name = name; this.price = price;
}
formattedPrice(){
return ‘s’ + String(this.price);}}
A new business requirement comes in that requests a ClothingItem class that should have all of the properties and methods of the Item class but will also have properties that are specific to clothes.
Which line of code properly declares the clothingItem class such that it inherits from Item?

• A. Class ClothingItem implements Item{
• B. Class ClothingItem {
• C. Class ClothingItem super Item {
• D. Class ClothingItem extends Item {

Answer: D

NEW QUESTION 3
A developer is debugging a web server that uses Node.js The server hits a runtimeerror 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 he 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 breakdown is hit ?

• A. node -i index.js
• B. Node --inspect-brk index.js
• C. Node inspect index.js
• D. Node --inspect index.js

Answer: D

NEW QUESTION 4
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);

Answer: BC

NEW QUESTION 5
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))
.t hen (value => (
Let result = ‘$(value) the race.’;)}
.catch(arr => {
console.log(“Race is cancelled.”, err);
});
What isthe value of result when Promise.race executes?

• A. Car 3 completes the race
• B. Car 2 completed the race.
• C. Car 1 crashed in the race.
• D. Race is cancelled.

Answer: B

NEW QUESTION 6
Referto the code below: Const pi = 3.1415326, What is the data type of pi?

• A. Double
• B. Number
• C. Decimal
• D. Float

Answer: B

NEW QUESTION 7
Which statement accurately describes the behaviour of the async/ await keyworks ?

• A. The associated class contains some asynchronous functions.
• B. The associated function will always return apromise
• C. The associated function can only be called via asynchronous methods
• D. The associated sometimes returns a promise.

Answer: B

NEW QUESTION 8
Refer to the following object:

How can a developer access the fullName property for cat?

• A. cat.fullName
• B. cat.fullName()
• C. cat.get.fullName
• D. cat.function.fullName()

Answer: A

NEW QUESTION 9
Refer to the code below:
1 let car1 = new promise((_, reject) =>
2 setTimeout(reject, 2000, “Car 1 crashed in”));
3 let car2 = new Promise(resolve => setTimeout(resolve, 1500, “Car 2 completed”));
4 let car3 = new Promise(resolve => setTimeout (resolve, 3000, “Car 3 Completed”));
5 Promise.race([car1, car2, car3]) 06 .then(value => (
07 let result = $(value) the race. `; 08 ))
9 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.

Answer: C

NEW QUESTION 10
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’]

Answer: B

NEW QUESTION 11
Refer to code below:

What is displayed when the code executes?

• A. ReferenceError: b is not defined
• B. a
• C. Undefined
• D. Null

Answer: C

Explanation:

NEW QUESTION 12
Refer to the code:

Given the code above, which three properties are set pet1? Choose 3answers:

• A. Name
• B. canTalk
• C. Type
• D. Owner
• E. Size

Answer: BCE

NEW QUESTION 13
A developer is wondering whether to use, Promise.then or Promise.catch, especially when a Promise throws an error?
Which two promises are rejected? Which 2 are correct?

• A. Promise.reject(‘cool error here’).then(error => console.error(error));
• B. Promise.reject(‘cool error here’).catch(error => console.error(error));
• C. New Promise((resolve, reject) => (throw ‘cool error here’}).catch(error => console.error(error)) ;
• D. New Promise(() => (throw ‘cool error here’}).then(null, error => console.error(error)));

Answer: BC

NEW QUESTION 14
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?

• A. Event.clicked
• B. e.nodeTarget ==this
• C. event.target.nodeName == ‘BUTTON’
• D. button.addEventListener(‘click’)

Answer: C

NEW QUESTION 15
A developer creates a generic function to log custom messages in the console. To do this, the function below is implemented.

Which three console logging methods allow the use of string substitution in line 02?

• A. Assert
• B. Log
• C. Message
• D. Info
• E. Error

Answer: AD

NEW QUESTION 16
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?

• A. 2 1 4 3 5
• B. 2 5 13 4
• C. 1 2 4 3 5
• D. 1 2 5 3 4

Answer: B

NEW QUESTION 17
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