Practice 50 JavaScript Array Programming Questions

Practice 50 JavaScript Array Programming Questions

Q1. Write a JavaScript program to find the length of an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: 4

Q2. Write a JavaScript program to add an element to the end of an array.  
Input: arr = [1, 2, 3], element = 4  
Expected Output: [1, 2, 3, 4]

Q3. Write a JavaScript program to add an element to the beginning of an array.  
Input: arr = [2, 3, 4], element = 1  
Expected Output: [1, 2, 3, 4]

Q4. Write a JavaScript program to remove the last element of an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: [1, 2, 3]

Q5. Write a JavaScript program to remove the first element of an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: [2, 3, 4]

Q6. Write a JavaScript program to find the index of an element in an array.  
Input: arr = [10, 20, 30, 40], element = 30  
Expected Output: 2

Q7. Write a JavaScript program to check if an array contains a specific element.  
Input: arr = [1, 2, 3, 4], element = 3  
Expected Output: true

Q8. Write a JavaScript program to find the largest number in an array.  
Input: arr = [10, 20, 4, 45, 99]  
Expected Output: 99

Q9. Write a JavaScript program to find the smallest number in an array.  
Input: arr = [10, 20, 4, 45, 99]  
Expected Output: 4

Q10. Write a JavaScript program to sort an array in ascending order.  
Input: arr = [4, 2, 5, 1, 3]  
Expected Output: [1, 2, 3, 4, 5]

Q11. Write a JavaScript program to sort an array in descending order.  
Input: arr = [4, 2, 5, 1, 3]  
Expected Output: [5, 4, 3, 2, 1]

Q12. Write a JavaScript program to reverse an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: [4, 3, 2, 1]

Q13. Write a JavaScript program to join two arrays.  
Input: arr1 = [1, 2], arr2 = [3, 4]  
Expected Output: [1, 2, 3, 4]

Q14. Write a JavaScript program to find the sum of all elements in an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: 10

Q15. Write a JavaScript program to find the average of all elements in an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: 2.5

Q16. Write a JavaScript program to remove a specific element from an array.  
Input: arr = [1, 2, 3, 4], element = 3  
Expected Output: [1, 2, 4]

Q17. Write a JavaScript program to concatenate two arrays.  
Input: arr1 = [1, 2], arr2 = [3, 4]  
Expected Output: [1, 2, 3, 4]

Q18. Write a JavaScript program to check if an array is empty.  
Input: arr = []  
Expected Output: true

Q19. Write a JavaScript program to find the median of an array.  
Input: arr = [1, 2, 3, 4, 5]  
Expected Output: 3

Q20. Write a JavaScript program to find the mode of an array.  
Input: arr = [1, 2, 3, 3, 4]  
Expected Output: 3

Q21. Write a JavaScript program to find the unique elements in an array.  
Input: arr = [1, 2, 2, 3, 4, 4]  
Expected Output: [1, 2, 3, 4]

Q22. Write a JavaScript program to merge two sorted arrays.  
Input: arr1 = [1, 4, 6], arr2 = [2, 3, 5]  
Expected Output: [1, 2, 3, 4, 5, 6]

Q23. Write a JavaScript program to find the intersection of two arrays.  
Input: arr1 = [1, 2, 3], arr2 = [2, 3, 4]  
Expected Output: [2, 3]

Q24. Write a JavaScript program to find the union of two arrays.  
Input: arr1 = [1, 2, 3], arr2 = [3, 4, 5]  
Expected Output: [1, 2, 3, 4, 5]

Q25. Write a JavaScript program to find the difference between two arrays.  
Input: arr1 = [1, 2, 3], arr2 = [2, 3, 4]  
Expected Output: [1]

Q26. Write a JavaScript program to find the second largest number in an array.  
Input: arr = [1, 2, 3, 4, 5]  
Expected Output: 4

Q27. Write a JavaScript program to find the second smallest number in an array.  
Input: arr = [1, 2, 3, 4, 5]  
Expected Output: 2

Q28. Write a JavaScript program to duplicate each element in an array.  
Input: arr = [1, 2, 3]  
Expected Output: [1, 1, 2, 2, 3, 3]

Q29. Write a JavaScript program to find the difference between two arrays.  
Input: arr1 = [1, 2, 3], arr2 = [3, 4, 5]  
Expected Output: [1, 2]

Q30. Write a JavaScript program to convert a string into an array of characters.  
Input: str = "hello"  
Expected Output: ["h", "e", "l", "l", "o"]

Q31. Write a JavaScript program to check if an array is a subset of another array.  
Input: arr1 = [1, 2, 3], arr2 = [1, 2]  
Expected Output: true

Q32. Write a JavaScript program to find the number of occurrences of a specific element in an array.  
Input: arr = [1, 2, 3, 1, 1, 4], element = 1  
Expected Output: 3

Q33. Write a JavaScript program to check if all elements of an array are unique.  
Input: arr = [1, 2, 3, 4, 5]  
Expected Output: true

Q34. Write a JavaScript program to remove all occurrences of a specific element from an array.  
Input: arr = [1, 2, 3, 4, 2], element = 2  
Expected Output: [1, 3, 4]

Q35. Write a JavaScript program to find the common elements between three arrays.  
Input: arr1 = [1, 2, 3], arr2 = [2, 3, 4], arr3 = [3, 4, 5]  
Expected Output: [3]

Q36. Write a JavaScript program to create an array of even numbers from 1 to 100.  
Input: range = 100  
Expected Output: [2, 4, 6, 8, ..., 100]

Q37. Write a JavaScript program to create an array of odd numbers from 1 to 100.  
Input: range = 100  
Expected Output: [1, 3, 5, 7, ..., 99]

Q38. Write a JavaScript program to calculate the product of all elements in an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: 24

Q39. Write a JavaScript program to find the first repeated element in an array.  
Input: arr = [1, 2, 3, 4, 1]  
Expected Output: 1

Q40. Write a JavaScript program to check if two arrays are equal.  
Input: arr1 = [1, 2, 3], arr2 = [1, 2, 3]  
Expected Output: true

Q41. Write a JavaScript program to create an array of multiples of a number.  
Input: num = 3, range = 5  
Expected Output: [3, 6, 9, 12, 15]

Q42. Write a JavaScript program to find the largest even number in an array.  
Input: arr = [1, 2, 3, 4, 5]  
Expected Output: 4

Q43. Write a JavaScript program to find the largest odd number in an array.  
Input: arr = [1, 2, 3, 4, 5]  
Expected Output: 5

Q44. Write a JavaScript program to generate an array of random numbers.  
Input: length = 5, min = 1, max = 100  
Expected Output: [random values between 1 and 100]

Q45. Write a JavaScript program to find the sum of squares of all elements in an array.  
Input: arr = [1, 2, 3, 4]  
Expected Output: 30

Q46. Write a JavaScript program to check if an array contains only numbers.  
Input: arr = [1, 2, "three", 4]  
Expected Output: false

Q47. Write a JavaScript program to find the largest prime number in an array.  
Input: arr = [1, 2, 3, 4, 5, 6]  
Expected Output: 5

Q48. Write a JavaScript program to find the average of even numbers in an array.  
Input: arr = [1, 2, 3, 4, 5, 6]  
Expected Output: 4

Q49. Write a JavaScript program to check if an array contains a sequence of numbers.  
Input: arr = [1, 2, 3, 4], sequence = [2, 3]  
Expected Output: true

Q50. Write a JavaScript program to convert an array into a string with a custom delimiter.  
Input: arr = [1, 2, 3], delimiter = "-"  
Expected Output: "1-2-3"