Question 1: Difference Between "null" and "undefined" data type with example? Question 2: What type of variable should you initialize at the time of declaration? Question 3: Guess the Output and Explain Why?
let languages = "java javaScript python cSharp";
let result = languages.lastIndexOf("S");
console.log(result)
Question 4: Guess the Output and Explain Why?
let variable = "hello programmers";
let result = Number(variable);
console.log(result);
Question 5: Guess the Output and Explain Why?
let num1 = 32;
let num2 = "32";
let result1 = num1 !== num2;
let result2 = num1 != num2;
console.log(result1,result2);
Question 6: Guess the Output and explain Why?
let str = "Hello Programmers";
let result = str.includes("r");
console.log(result);
Question 7: Guess the Output and Explain Why?
let num1 = 2;
let num2 = 5;
let result = num1**num2*2;
console.log(result);
Question 8: Guess the Output and Explain Why?
let num1 = [1,2,4,5];
let num2 = [6,5,8,0];
let result = num1.concat(num2);
console.log(result)
Question 9: Guess the Output and Explain Why?
let a = 5;
let b = 7;
let c = 8;
let result = a<b>c;
console.log(result)
Question 10: If your state split into four equal parts such that in each part there are 1/4 number of people live. You have to find How many people would live in each part?
Question 1: Guess the Output And Explain Why?
let i = 4;
for(let j = 0;i<10;i++){
if(j === 1 || i === 6){
continue;
}
else{
console.log(i,j);
if(i === 7){
break;
}}}
Question 2: Guess the Output and Explain Why?
let i = 0;
for(i;i<5;i++){
console.log(i);
}
Question 3: Write a simple Program in which You have to print first 10 number in descending order?
Question 4: Lets say John is looking a new country to live in. He want to live in a country that speaks English, has less than 10 million people. One of the food option between these two must present Spanish food Or English food.
Write an if statement to help john figure out Your country is right for him?
Question 5: Guess the Output And Explain Why?
for(let i = 0;i<10;i++){
console.log(i);
}
console.log(i)
Question 6: use nested-if statement to check your age>18
than check your height height > 5.10.
If both true show any message(I can sit in __ exam) in the console?
Question 7: Create two variables grade and passingYear.Check if your grade == "A" and passingYear < 2020 with the help of ternary operator(Not allowed to use any logical operator).If both condition true print on console Qualify. Otherwise Fail
Question 1: Create a function Declaration called describeYourState Which take three parameters 'Population', 'traditional food' and 'historical place'. Based on this input function should return a string with this format. My state population is __. Its traditional food is __ and historical place name is __
Question 2: Create a function expression which does the exact same thing as defined in Question 1
Question 3: Create function addition which takes two numbers as an argument. And return the result of sum of two numbers
Important Note In the function call you are not allowed to pass any parameter.
Example
function addition(num1,num2){
return num1 + num2;
}
console.log(addition()); //You are not allowed to modify this line any more
Question 4: Identify which type of value passed below into the function greet()
let person = {
name:"john",
age:25
}
function greet(person){
person.name = `Mr ${person.name}`
console.log(`Welcome ${person.name}`)
}
greet(person)
Question 5: Create higher order function named as transformer which take string and firstUpperCaseWord() as an arguments. And return string with first word in upperCase
Question 6: create function which will display Your name after every 5 seconds
input
let yourName = "john";
output
"john" after 5 second
"john" after 5 second
"john" after 5 second
"john" after 5 second
.
.
.
and so on.
Question 7: Guess the Output And Explain Why?
let arrowFunction = (name ="Coders") => {`Welcome ${name}`};
console.log(arrowFunction("Programmers"));
Question 1: Guess the Output And Explain Why?
console.log(Math.round(Math.random() * 10 ));
Question 2: Create an object called 'Country' for a country of your choice, containing properties 'country', 'capital', 'language', 'population' and 'neighbours'
- Increase the country population by two million using dot notation.
- Decrease the country population by one million using bracket notation.
Question 3: Guess the Output and explain Why?
let car = {
color:"Blue",
model:2021,
company:"Toyota"
}
let carColor = "Blue";
console.log(car[carColor]);
console.log(car.carColor);
Question 4: Create a method describeCar inside car object in which you have to print like this in console using template literals
Company of my car is __ . It color is __ And Model of my car is __
Question 5: Generate random numbers between 0 and 10 using trunc method of MATH object
Example
getRandomNumbers(){
}
Ouput value 0-10
Question 6: Guess the Output and Explain Why?
let arr = [1,2,3,4];
arr.forEach(elem =>{
if(elem == 1){
continue;
}
console.log(elem);
})
Question 7: Guess the Output And explain Why?
Important Note if there is any error How we can solve that error?
let airplane = {
flightName:"fly india",
atacode:"FI",
ratings:4.9,
book(passenger,flightNum){
console.log(`${passenger} Booked flight in ${this.flightName} with flight Number ${this.atacode}${flightNum}`);
}
}
let bookMethod = airplane.book;
bookMethod("john",8754);
Question 8: Guess the Output And Explain Why?
let arr = [1,2,3,4];
for(let elem in arr){
console.log(elem);
}
Question 1: Explain difference between innerText and innerHTML in the following example?
HTML
<div id="content">
<h2> Hello Coders</h2>
</div>
JavaScript
let content = document.getElementById("content")
console.log(content.innerHTML)
console.log(content.innerText)
Question 1: Create regex for password with the following validations.
- Length of password at least of 8 characters
- contain at least one special character
- contain at least one alphabet (a-z) character
HTML
<form action="" class="testForm">
<input type="password" name="" class="inputPass" placeholder="Enter Password" >
<input type="submit" value="Check Password">
</form>
JavaScript
let form = document.querySelector('.testForm')
let inputPassword = document.querySelector('.inputPass');
let requiredPasswordPattern = "create your regex here";
form.addEventListener('submit' , (e)=>{
e.preventDefault();
let password = inputPassword.value;
let result = requiredPasswordPattern.test(password);
if(result == true){
console.log("Your password validated successfully")
}else{
console.log("try again with new password")
}
})
Question 1: You have given array of strings. Your task is to obtain last two elements of given array using slice method?
Input
let admins = ["john","paul","Neha","harry"];
Ouput
["Neha","harry"];
Question 2: You have given an array of 5 elements(1-5). Your task is defined as below.
- You have to delete 2 elements starting from index 2.
- You have to add 3 new elements on that position of Your choice.
- Display the 2 deleted elements in console.
Question 3: What happens if we use negative number inside slice method? Example : arr.slice(-2);
Question 4: Write three different methods/approaches to get last element of the array?
Question 5: You have given an array of nums. Create new Array with the help of nums array. In new Array each element will be a result of multiplication by 2 of the original array element
Example:
Input
let nums = [1,2,3,4,5];
output
updatedNums = [2,4,6,8,10]
Question 6 You have given an array of scores in which score of each student stored. Create a new array with the help of original scores array in which only those scores exist greater than 75%
let totalScore = 150;
let scores = [55,76,35,77,88,97,120,136,140];
Question 7: You have given an array of numbers nums. You have to find sum of all array elements using reduce method?
let nums = [2,3,5,7,8,4,9];
Question 8: You have given an array of numbers nums. You have to find the index of value 8 using built-in method of array?
let nums = [2,3,5,6,8,6,4,8];
Question 9: You have given an array of objects of users as below. Find the specified user with name property = "John". Also find the position (index+1) of that user inside the array?
let users = [
{
name:"Paul",
age:24,
verified:true
},
{
name:"John",
age:21,
verified:false
},
{
name:"Neha",
age:19,
verify:true
},
]
Question 10: Guess the Output and explain Why?
let nums = [1,2,4,5,[6,[8]],[9,0]];
let res1 = nums.flat(1);
let res2 = nums.flatMap(elem => elem);
console.log(res1,res2);
Question 11: You have given an array of nums. Write a program to sort the elements of array in descending order using built-in method of array.
Input
let nums = [5,1,4,6,8,3,9];
Output
[9,8,6,5,4,3,1]
Question 12: Guess the Output and Explain Why?
let arr = [1,2,3,4];
let result = arr.splice(1,2).pop();
console.log(result);
Question 13: You have given an array of numbers nums. You have to check if all elements of the array > 15 using built-in array method.
let nums = [16,17,18,28,22];
Question 1: How can we get current time in millisecond?
Question 2: Guess the Output and Explain Why?
let currentDate = new Date();
let result1 = currentDate.getDay();
let result2 = currentDate.getDate();
console.log(result1,result2)
Question 1: Create two variables myHobby , age . Now set their value in local storage(according to your hobby and age).
After setting also get value from local storage and display their values in console.
Question 1: Your tasks:
- Use a constructor function to implement a 'Bike'. A bike has a 'make' and a 'speed' property. The 'speed' property is the current speed of the bike in km/h
- Implement an 'accelerate' method that will increase the bike's speed by 50, and log the new speed to the console
- Implement a 'brake' method that will decrease the bike's speed by 25, and log the new speed to the console
- Create 2 'Bike' objects and experiment with calling 'accelerate' and 'brake' multiple times on each of them
Sample Data
Data car 1: 'bike1' going at 120 km/h Data car 2: 'bike2' going at 95 km/h
Question 2: Re-create Question 1 But this time using ES6 class.
Question 3: Guess the Output And Explain Why?
function Person(name){
this.name = name;
}
let me = new Person("John");
console.log(me.__proto__ == Person.prototype);
console.log(me.__proto__.__proto__ == Object.prototype);
Question 4: Create constructor function inside Car class with three properties color , model , company
class Car {
}
Question 5: Identify all mistakes in the following class
class Car = {
constructor(){
},
engineMethod = function(){
console.log("This is engine method of Car class");
}
}
Question 6: Guess the Output and explain Why? And if there is any error How we can remove that error?
function Person(name,age){
this.name = name;
this.age = age;
this.brainMethod = function(){
console.log("This is brain method of Person")
}
}
Person.heartMethod = function(){
console.log("This is heart method of Person");
}
let me = new Person("john",34);
me.brainMethod();
me.heartMethod();
Question 7: Create a new class Animal (which will be child class) inherited from Person class. In Addition in Animal class Add some additional properties like breedType and animalFamily.(catFamily, dogFamily)
Question 8: Guess the Output And Explain Why?
class Car {
constructor(){
}
}
let car = new Car();
console.log(Car.prototype.isPrototypeOf(Car));
console.log(Car.prototype.isPrototypeOf(car));
Question 1: Guess the Output And Explain Why? Html Code
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>JavaScript-CoderDost</title>
<style>
</head>
<body>
<div id="content">
<h2 id = "heading" ></h2>
</div>
<script defer src = "./script.js"></script>
</script>
</body>
</html>
JS Code
async function greeting() {
let myPromise = new Promise(function(resolve) {
setTimeout(function() {resolve("I love Programming !!");}, 2000);
});
document.getElementById("heading").innerHTML = await myPromise;
}
greeting();
Question 2: Find the Logical Error in below code. And How can we solve them with callback function approach?
const movies = [
{ title: `Movie 1`},
{ title: `Movie 2` }
]
function getMovies(){
setTimeout(() => {
movies.forEach((movie, index) => {
console.log(movie.title)
})
}, 1000);
}
function createMovies(movie){
setTimeout(() => {
movies.push(movie)
}, 2000);
}
getMovies();
createMovies({ title: `Movie 3`} )
Question 3: What are the three possible State of any promise?
Question 4: Solve Question 2 again But this time with the help of promise
Question 5: Now re-factor Question 2 with the help of async-await keyword?
Question 6: Status code starting with 300 represent which type of message/error?
Question 1: Guess the Output and Explain Why?
let arr = [3,4,5,7,98,0];
let [a,b,,c] = arr;
console.log(a,b,c);
Question 2: Guess the Output And Explain Why?
let arr = [1,3,[2,55],[9,8,7]];
let [a,,[b,c],d] = arr;
console.log(a,b,c,d);
Question 3: Guess the Output and explain Why?
let obj = {
name:"John",
age:25,
weight:70
}
let {name:objName,age} = obj;
console.log(name,age);
Question 4: You have given an array of nums.Create shallow copy of that array and store them in another variable
let nums = [5,7,4,9,2,8];
let newNums = "store Shallow copy of nums inside newNums variable")
Question 5: You have given an array as below . Create a function which accept elements as an argument and return last 4 element of the array
Example:
let nums = [1,2,3,4,5,6,7,8];
input data: 1,2,3,4,5,6,7,8
output data: 5,6,7,8
Question 6: Guess the Output And Explain Why?
let nums = 0;
let result = nums ?? 50;
console.log(result);
Question 7: You have given an object as below. You have to check wheather physics is the subject of that student or not, if true find the score of physics subject using optional chaining
let student = {
Math:{
score:75,
},
physics:{
score:85,
}
}
Question 8: Guess the Output And Explain Why?
let nums = [2,3,4,5,6];
for(let key of nums) {
console.log(key)
}
Question 1: You have given scenario. You are in script.js And in same directory there is another file products.js. In products.js there are two methods called createProduct and deleteProduct
write an import and export statement properly in order to import these two methods from products.js file into the script.js
Question 2 Now export only one method createProduct using default export statement?
Question 3: In importing statement how can we customize/change the name of function we are importing?