All About Free JavaScript-Developer-I Free Exam Questions

NEW QUESTION 1
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?

• A. EndStart Success
• B. StartSuccess End
• C. StartEnd Success
• D. Success Start End

Answer: C

NEW QUESTION 2
Refer to the code below: Function changeValue(obj) { Obj.value =obj.value/2;
}
Const objA = (value: 10);
Const objB = objA; changeValue(objB); Const result = objA.value;
What is the value of result after the code executes?

• A. 10
• B. Nan
• C. 5
• D. Undefined

Answer: C

NEW QUESTION 3
Given the following code: Let x =null; console.log(typeof x);
What is the output of the line 02?

• A. “Null”
• B. “X”
• C. “Object”
• D. “undefined”

Answer: C

NEW QUESTION 4
In which situation should a developer include a try .. catch block around their function call ?

• A. The function has an error that shouldnot be silenced.
• B. The function results in an out of memory issue.
• C. The function might raise a runtime error that needs to be handled.
• D. The function contains scheduled code.

Answer: C

NEW QUESTION 5
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 6
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:

• A. Non-primitive values are mutable.
• B. Non-primitive values are immutable.
• C. Primitive values are mutable.
• D. Primitive values are immutable.

Answer: D

NEW QUESTION 7
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
2 //missing line 03
04 ).0);
Which missing lines 02 and 03 return the correct count?

• A. Yes
• B. Not Mastered

Answer: A

NEW QUESTION 8
The developer wants to test this code:
Const toNumber =(strOrNum) => strOrNum; Which two tests are most accurate for this code? Choose 2 answers

• A. console.assert(toNumber(‘2’) ===2);
• B. console.assert(Number.isNaN(toNumber()));
• C. console.assert(toNumber(‘-3’) < 0);
• D. console.assert(toNumber () === NaN);

Answer: AC

NEW QUESTION 9
Why would a developer specify a package.jason as a developed forge instead of a dependency ?

• A. It is required by the application in production.
• B. It is only needed for local development and testing.
• C. Other requiredpackages depend on it for development.
• D. It should be bundled when the package is published.

Answer: B

NEW QUESTION 10
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 11
Which codestatement below correctly persists an objects in local Storage ?

• A. const setLocalStorage = (storageKey, jsObject) => { window.localStorage.setItem(storageKey, JSON.stringify(jsObject));}
• B. const setLocalStorage = ( jsObject) => { window.localStorage.connectObject(jsObject));}
• C. const setLocalStorage = ( jsObject) => { window.localStorage.setItem(jsObject);}
• D. const setLocalStorage = (storageKey, jsObject) => { window.localStorage.persist(storageKey, jsObject);}

Answer: A

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
Refer to the code:

Given the requirement to refactor the code above to JavaScript class format, which class definition is correct?
A)

B)

C)

D)

• A.

Answer: B

NEW QUESTION 14
developer publishes a new version of a package with new features that do not break backward compatibility. The previous version number was 1.1.3.
Following semantic versioning format, what should the new package version number be?

• A. 2.0.0
• B. 1.2.3
• C. 1.1.4
• D. 1.2.0

Answer: D

NEW QUESTION 15
Considering type coercion, what does the following expression evaluate to? True + ‘13’ + NaN

• A. ‘ 113Nan ’
• B. 14
• C. ‘ true13 ’
• D. ‘ true13NaN ’

Answer: D

NEW QUESTION 16
developer is trying to convince management that their team will benefit from using
Node.js for a backend server that they are going to create. The server will be a web server that handles API requests from a website that the team has already built using HTML, CSS, and JavaScript.
Which three benefits of Node.js can the developer use to persuade their manager? Choose 3 answers:

• A. I nstalls with its own package manager toinstall and manage third-party libraries.
• B. Ensures stability with one major release every few years.
• C. Performs a static analysis on code before execution to look for runtime errors.
• D. Executes server-side JavaScript code to avoid learning a new language.
• E. User non blocking functionality for performant request handling .

Answer: ACE

NEW QUESTION 17
developer creates a new web server that uses Node.js. It imports aserver library that uses events and callbacks for handling server functionality.
The server library is imported with require and is made available to the code by a
variable named server. The developer wants to log any issues that the server has while booting up.
Given the code and the information the developer has, which code logs an error at boost with an event?

• A. Server.catch ((server) => { console.log(‘ERROR’, error);});
• B. Server.error ((server) => { console.log(‘ERROR’, error);});
• C. Server.on (‘error’, (error) => { console.log(‘ERROR’, error);});
• D. Try{server.start();} catch(error) { console.log(‘ERROR’, error);}

Answer: C

NEW QUESTION 18
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