JavaScript Training in Kovilpatti

1. Write a function replaceChar that replaces all occurrences of a specific character in a string with another character.
2. Write code to extract the substring between two specific characters in a string.
3. Write a JavaScript program to check whether a string starts with ‘Java’ if it does not otherwise.
4. Write a JavaScript program to check whether a given string contains an equal number of p’s and t’s.
5. Write a JavaScript program to create a new string without the first and last characters of a given string.
6. Write a JavaScript program to create a new string from a given string. This program removes the first and last characters of the string if the first or last character is ‘P’. Return the original string if the condition is not satisfied.
7. Write a JavaScript program that returns a subset of a string.

           Sample Data: dog

          Expected Output: [“d”, “do”, “dog”, “o”, “og”, “g”]

8. Write a JavaScript program to replace each character in a given string with the next in the English alphabet.

Note: ‘a’ will be replaced by ‘b’ or ‘z’ would be replaced by ‘a’.

1. Given an array let arr = [1, 2, 3, 4, 5], set the value of the element at index 2 to 10. Print the updated array.
2. Given an array of numbers [3, 5, 7, 2, 8], find and print the maximum value in the array.
3. Given the array [‘apple’, ‘banana’, ‘cherry’, ‘date’], find all fruits that contain the letter ‘a’.
4. Given the array [‘apple’, ‘banana’, ‘apple’, ‘orange’], find the index of the last occurrence of ‘apple’.
5. Write a JavaScript program to find the most frequent item in an array.

          Sample array : var arr1=[3, ‘a’, ‘a’, ‘a’, 2, 3, ‘a’, 3, ‘a’, 2, 4, 9, 3];

6. Given an array of numbers with duplicates, such as [1, 2, 3, 2, 4, 1, 5], create a new array with duplicates removed.

7. Given an array of numbers [10, 20, 30, 40, 50], calculate the sum of all the numbers.

1. Write code to  calculate a grade for the inputted mark  based on the following scale:
   • 90–100: “A”
   • 80–89: “B”
   • 70–79: “C”
   • 60–69: “D”
   • Below 60: “F”
2. Check if a Person is Eligible to Vote. (age as input from the user).
3. Determine if a Year is a Century Year. (year as input from the user).
4. Check if a Year is a Leap Year. (year  as input from the user using a form).
5. Write a function findQuadrant that determines the quadrant of a point (x, y) in a 2D coordinate system:
   • Quadrant I: x > 0, y > 0
   • Quadrant II: x < 0, y > 0
   • Quadrant III: x < 0, y < 0
   • Quadrant IV: x > 0, y < 0
   • Origin: x == 0, y == 0
6. Write a code to  apply a discount based on the total amount:
   • Total >= 100: 20% discount
   • Total >= 50 and < 100: 10% discount
   • Less than 50: No discount

1. Write a JavaScript conditional statement to find the largest of five numbers. Display an alert box to show the results.

          Sample numbers : -1,3,4,6,0

          Output : 6 

     2. Write a JavaScript program that iterates integers from 1 to 100. But for multiples of three print “Fizz” instead of the number and for multiples of five print “Buzz”. For numbers multiples of both three and five print “FizzBuzz”.

    3. Write a JavaScript program to construct the following pattern, using a nested for loop.

*  

* *  

* * *  

* * * *  

* * * * *

       4. Write a JavaScript program that prints the elements of the following array. Note : Use nested for loops.

Sample array : var a = [[1, 2, 1, 24], [8, 11, 9, 4], [7, 0, 7, 27], [7, 4, 28, 14], [3, 10, 26, 7]];

Sample Output :

“row 0”

” 1″

” 2″

” 1″

” 24″

“row 1”

       5. Write a JavaScript for loop that iterates from 0 to 15. For each iteration, it checks if the current number is odd or even, and displays a message on the screen.

Sample Output :

“0 is even”

“1 is odd”

“2 is even”

1. Write a function makeMultiplier that takes a number x and returns a new function that multiplies its argument by x.
2.  Write a function isPalindrome that checks if a given string is a palindrome (reads the same forward and backward).
3. Write a function count_consonant that takes a string and returns the number of consonants (other than – a, e, i, o, u) in it.
4. Write a function findMedian that finds the median of an array of numbers.
5. Write a recursive function factorial that calculates the factorial of a given number n.
6. Write a function findLargest that takes three numbers and returns the largest one using conditional statements.
7. Write a function isPrime that checks if a given number is a prime number.
8. Write a function dayOfWeek that takes a number from 0 to 6 and returns the corresponding day of the week. (0 for Sunday, 1 for Monday, etc.)
9. Write a function isLeapYear that checks if a given year is a leap year. A year is a leap year if it is divisible by 4, but not divisible by 100, unless it is also divisible by 400.
10. The  function takes a single parameter,X , and returns an anonymous function that takes a single parameter,Y, and returns the product of  and  (i.e.: ).X * Y
11. Write an arrow function that takes a single number as an argument and returns that number squared.
12. Write an arrow function that filters an array of numbers, returning only the even numbers.
13. Write an arrow function that takes a string and a number. If the number is not provided, default it to 1. Return the string repeated by the number of times specified.

1. Write a function that calculates the number of days between two given dates.
2. Write a function that takes a birthdate (in the format YYYY-MM-DD) and returns the person’s age in years.
3. Write a function that compares two dates and returns which one is earlier, later, or if they are the same.
4. Write a function that takes a date and returns the day.
5. Write a function that returns the current date and time in the format YYYY-MM-DD HH:MM:SS.

1. Write a JavaScript function that takes a number as a parameter and throws a custom ‘Error’ if the number is not an integer.
2. Write a JavaScript function that accepts two numbers as parameters  n1 and n2 to calculate n1/n2 and throws a custom ‘Error’ if the second number is zero.
3. Write a JavaScript program that uses a try-catch block to catch and handle a ‘RangeError’ when accessing an array with an invalid index.
4. Write a JavaScript function that takes a string as a parameter and throws a custom ‘Error’ if the string is empty.
5.  Write a JavaScript program to compute the exponent(power) of a number. (use recursion and handle the error if the given number is zero).

1. Write a JavaScript program to create a dropdown menu that shows and hides its options when clicked.
2. Write a JavaScript program that implements a “form” validation that displays an error message if a required field is left empty when submitting the form.
3. Write a JavaScript program to create a slideshow that changes the displayed image when a next or previous button is clicked.
4. Write a JavaScript program to create a progress bar that updates its width based on task completion i.e number of questions answered.

1. Write a JavaScript program to get the length of a JavaScript object.

         Sample object :

        var student = {

        name : “David Rayy”,

        sclass : “VI”,

        rollno : 12 };

     2. Write a JavaScript program to delete the rollno property from the following object. Also print the object before or after deleting the property.

        Sample object:

        var student = {

       name : “David Rayy”,

       sclass : “VI”,

        rollno : 12 };

     3. Write a JavaScript function to retrieve all the values of an object’s properties.

    4. Create an object representing a book with properties title, author, and details. The details property should be another object containing publishedYear and pages. Write code to access the publishedYear property.

   5. Write a JavaScript program to display the reading status (i.e. display book name, author name and reading status) of the following books.

        var library = [ 

      {

           author: ‘Bill Gates’,

           title: ‘The Road Ahead’,

           readingStatus: true

      },

    {

         author: ‘Steve Jobs’,

         title: ‘Walter Isaacson’,

         readingStatus: true

    },

   {

       author: ‘Suzanne Collins’,

      title:  ‘Mockingjay: The Final Book of The Hunger Games’, 

      readingStatus: false

    }];

1. Write a JavaScript program to create a class called “Person” with properties for name, age and country. Include a method to display the person’s details. Create two instances of the ‘Person’ class and display their details.
2. Write a JavaScript program that creates a class called “BankAccount” with properties for account number and balance. Include methods to deposit and withdraw money from the account. Create some instances of the “BankAccount” class, deposit some money, and withdraw a portion of it.
3.  Write a JavaScript program that creates a class `Book` with properties for title, author, and publication year. Include a method to display book details. Create a subclass called ‘Ebook’ that inherits from the ‘Book’ class and includes an additional property for book price. Override the display method to include the book price. Create an instance of the ‘Ebook’ class and display its details.
4.  Write a JavaScript program that creates a class called Product with properties for product ID, name, and price. Include a method to calculate the total price by multiplying the price by the quantity. Create a subclass called PersonalCareProduct that inherits from the Product class and adds an additional property for the warranty period. Override the total price calculation method to include the warranty period. Create an instance of the PersonalCareProduct class and calculate its total price.

1. Create a set containing 0 to 10 using a loop.
2. const a = [4, 5, 8, 9]

        const b = [3, 4, 5, 7]

        Find the common elements from the set and display in the document.

     3. Create a Map from an array and display it on the console.

       countries = [

       [‘Finland’, ‘Helsinki’],

      [‘Sweden’, ‘Stockholm’],

      [‘Norway’, ‘Oslo’],

       ]

     4. [

       { English: 91 },

       { French: 45 },

       { Arabic: 25 },

       { Spanish: 24 },

       { Russian: 9 },

       { Portuguese: 9 },

       { Dutch: 8 },

       { German: 7 },

       { Chinese: 5 },

       { Swahili: 4 },

       { Serbian: 4 }

       ]

      Display the three most spoken languages.

    5. Find the union of set A and set B (A U B) using Spread Operator.

    let a = [1, 2, 3, 4, 5]

    let b = [3, 4, 5, 6]

1. Write a JavaScript function that takes a callback to multiply two numbers and invokes it after a delay of 2 seconds.
2. Print in console 1, 2, 3, 4, 5 … 10, after each and every second. Means 1 after 1 sec, 2 after 2 sec, 3 after 3 sec and so on. How would you do it?
3. Write a promise chain that first resolves with a number, then adds 5 to it, and finally multiplies the result by 2.
4. Write a function that takes an array of promises and uses Promise.all to resolve them. The function should return a promise that resolves with an array of results.
5. Write a function that performs two asynchronous operations sequentially using promises. The first operation should be a delay of 1 second, and the second should be another delay of 2 seconds. Log a message after both operations are complete.
6. Write a function that creates a promise that rejects with an error message. Use .catch() to handle the error and log it.
7. Rewrite a function that uses promises with .then() to use async/await instead.
8. Fetch an External Api of your choice and manipulate it to  display contents on user interaction on the screen. For example: Recipe for a dish inputted, Jokes ,Weather of the city inputted.