Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

In JavaScript, how do you turn an Object into an Array []?

Answer»
let obj = { id: "1", name: "user22", age: "26", work: "programmer" };

//Method 1: Convert the keys to Array using - Object.keys()
console.log(Object.keys(obj));
// ["id", "name", "age", "work"]

// Method 2 Converts the Values to Array using - Object.values()
console.log(Object.values(obj));
// ["1", "user22r", "26", "programmer"]

// Method 3 Converts both keys and values using - Object.entries()
console.log(Object.entries(obj));
//[["id", "1"],["name", "user22"],["age", "26"],["work", “programmer"]]
Discussion
2.

Write the code to find the vowels

Answer»
const findVowels = str => {
let count = 0
const vowels = ['a', 'e', 'i', 'o', 'u']
for(let char of str.toLowerCase()) {
if(vowels.includes(char)) {
count++
}
}
return count
}
Discussion
3.

Write the code given If two strings are anagrams of one another, then return true.

Answer»
var firstWord = "Deepak";
var secondWord = "Aman";

isAnagram(wordOne, wordTwo); // true

function isAnagram(one, two) {
//Change both words to lowercase for case insensitivity..
var a = one.toLowerCase();
var b = two.toLowerCase();

// Sort the strings, then combine the array to a string. Examine the outcomes.
a = a.split("").sort().join("");
b = b.split("").sort().join("");

return a === b;
}
Discussion
4.

Write the code for dynamically inserting new components.

Answer»
<html>
<head>
<title>inserting new components dynamically</title>
<script type="text/javascript">
function addNode () { var newP = document. createElement("p");
var textNode = document.createTextNode(" This is other node");
newP.appendChild(textNode); document.getElementById("parent1").appendChild(newP); }
</script>
</head>
<body> <p id="parent1">firstP<p> </body>
</html>
Discussion
5.

Implement a function that returns an updated array with r right rotations on an array of integers a .

Answer»

Example:

Given the following array: [2,3,4,5,7]
Perform 3 right rotations:
First rotation : [7,2,3,4,5] , Second rotation : [5,7,2,3,4] and, Third rotation: [4,5,7,2,3]

return [4,5,7,2,3]

Answer:

function rotateRight(arr,rotations){
if(rotations == 0) return arr;
for(let i = 0; i < rotations;i++){
let element = arr.pop();
arr.unshift(element);
}
return arr;
}
rotateRight([2, 3, 4, 5, 7], 3); // Return [4,5,7,2,3]
rotateRight([44, 1, 22, 111], 5); // Returns [111,44,1,22]
Discussion
6.

Write a function that performs binary search on a sorted array.

Answer»
function binarySearch(arr,value,startPos,endPos){
if(startPos > endPos) return -1;

let middleIndex = Math.floor(startPos+endPos)/2;

if(arr[middleIndex] === value) return middleIndex;

elsif(arr[middleIndex > value]){
return binarySearch(arr,value,startPos,middleIndex-1);
}
else{
return binarySearch(arr,value,middleIndex+1,endPos);
}
}  
Discussion
7.

Guess the output of the following code:

Answer»
var x = 23;

(function(){
var x = 43;
(function random(){
x++;
console.log(x);
var x = 21;
})();
})();  Answer:

Output is NaN.

random() function has functional scope since x is declared and hoisted in the functional scope.

Rewriting the random function will give a better idea about the output:

function random(){
var x; // x is hoisted
x++; // x is not a number since it is not initialized yet
console.log(x); // Outputs NaN
x = 21; // Initialization of x
}
Discussion
8.

Guess the outputs of the following code:

Answer»
// Code 1:

let x= {}, y = {name:"Ronny"},z = {name:"John"};
x[y] = {name:"Vivek"};
x[z] = {name:"Akki"};
console.log(x[y]);

// Code 2:

function runFunc(){
console.log("1" + 1);
console.log("A" - 1);
console.log(2 + "-2" + "2");
console.log("Hello" - "World" + 78);
console.log("Hello"+ "78");
}
runFunc();

// Code 3:

let a = 0;
let b = false;
console.log((a == b));
console.log((a === b));

Answers:

Code 1 - Output will be {name: “Akki”}.

Adding objects as properties of another object should be done carefully.

Writing x[y] = {name:”Vivek”} , is same as writing x[‘object Object’] = {name:”Vivek”} ,

While setting a property of an object, javascript coerces the parameter into a string.

Therefore, since y is an object, it will be converted to ‘object Object’.

Both x[y] and x[z] are referencing the same property.

Code 2 - Outputs in the following order:

11
Nan
2-22
NaN
Hello78

Code 3 - Output in the following order due to equality coercion:

true
false
Discussion
9.

Guess the outputs of the following codes:

Answer»
// Code 1:

function func1(){
setTimeout(()=>{
console.log(x);
console.log(y);
},3000);

var x = 2;
let y = 12;
}
func1();

// Code 2:

function func2(){
for(var i = 0; i < 3; i++){
setTimeout(()=> console.log(i),2000);
}
}
func2();

// Code 3:

(function(){
setTimeout(()=> console.log(1),2000);
console.log(2);
setTimeout(()=> console.log(3),0);
console.log(4);
})();

Answers:



  • Code 1 - Outputs 2 and 12. Since, even though let variables are not hoisted, due to the async nature of javascript, the complete function code runs before the setTimeout function. Therefore, it has access to both x and y.


  • Code 2 - Outputs 3, three times since variable declared with var keyword does not have block scope. Also, inside the for loop, the variable i is incremented first and then checked.


  • Code 3 - Output in the following order:

2
4
3
1 // After two seconds

Even though the second timeout function has a waiting time of zero seconds, the javascript engine always evaluates the setTimeout function using the Web API, and therefore, the complete function executes before the setTimeout function can execute.
Discussion
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