Objective

In this challenge, we learn about iterating over objects. Check the attached tutorial for more details.

Task

Complete the function in the editor. It has one parameter: an array, a, of objects. Each object in the array has two integer properties denoted by x and y. The function must return a count of all such objects o in array a that satisfy o.x = o.y.

Objective

In this challenge, we practice using JavaScript classes. Check the attached tutorial for more details.

Task

Create a Polygon class that has the following properties:

• A constructor that takes an array of integer values describing the lengths of the polygon’s sides.
• A perimeter() method that returns the polygon’s perimeter.
  Locked code in the editor tests the Polygon constructor and the perimeter method.

Note: The perimeter method must be lowercase and spelled correctly.

Objective

In this challenge, we learn about strings and exceptions. Check out the attached tutorials for more details.

Task

Complete the reverseString function; it has one parameter, s. You must perform the following actions:

1. Try to reverse string s using the split, reverse, and join methods.
2. If an exception is thrown, catch it and print the contents of the exception’s message on a new line.
3. Print s on a new line. If no exception was thrown, then this should be the reversed string; if an exception was thrown, this should be the original string.

Objective

In this challenge, we practice using throw and catch statements to work with custom error messages.

Task

Complete the isPositive function below. It has one integer parameter, a. If the value of a is positive, it must return the string YES. Otherwise, it must throw an Error according to the following rules:

• If a is 0, throw an Error with message = Zero Error.
• If a is negative, throw an Error with message = Negative Error.

Objective

In this challenge, we learn about Arrays. Check out the attached tutorial for more details.

Task

Complete the getSecondLargest function in the editor below. It has one parameter: an array, nums, of n numbers. The function must find and return the second largest number in nums.

Objective

In this challenge, we practice looping over the characters of string. Check out the attached tutorial for more details.

Task

Complete the vowelsAndConsonants function in the editor below. It has one parameter, a string, s, consisting of lowercase English alphabetic letters (i.e., a through z). The function must do the following:

1. First, print each vowel in s on a new line. The English vowels are a, e, i, o, and u, and each vowel must be printed in the same order as it appeared in s.
2. Second, print each consonant (i.e., non-vowel) in s on a new line in the same order as it appeared in s.

Objective

In this challenge, we learn about switch statements. Check out the attached tutorial for more details.

Task

Complete the getLetter(s) function in the editor. It has one parameter: a string, s, consisting of lowercase English alphabetic letters (i.e., a through z). It must return A, B, C, or D depending on the following criteria:

• If the first character in string s is in the set {a, e, i, o, u}, then return A.
• If the first character in string s is in the set {b, c, d, f, g}, then return B.
• If the first character in string s is in the set {h, j, k, l, m}, then return C.
• If the first character in string s is in the set {n, p ,q,r, s, t, v, w, x, y, z}, then return D.

Hint: You can get the letter at some index i in s using the syntax s[i] or s.charAt(i).

Objective

In this challenge, we learn about if-else statements. Check out the attached tutorial for more details.

Task

Complete the getGrade(score) function in the editor. It has one parameter: an integer, score, denoting the number of points Julia earned on an exam. It must return the letter corresponding to her grade according to the following rules:

• If (25 < score <= 30), then grade = A.
• If (20 < score <= 25), then grade = B.
• If (15 < score <= 20), then grade = C.
• If (10 < score <= 15), then grade = D.
• If (5 < score <= 10), then grade = E.
• If (0 < score <= 5), then grade = F.

Objective

In this challenge, we practice declaring variables using the let and const keywords. Check out the attached tutorial for more details.

Task

1. Declare a constant variable, PI, and assign it the value Math.PI. You will not pass this challenge unless the variable is declared as a constant and named PI (uppercase).
2. Read a number, r, denoting the radius of a circle from stdin.
3. Use PI and r to calculate the area and perimeter of a circle having radius r.
4. Print area as the first line of output and print perimeter as the second line of output.

Objective

Today, we’re discussing JavaScript functions. Check out the attached tutorial for more details.

Task

Implement a function named factorial that has one parameter: an integer, n. It must return the value of n! (i.e., n factorial).