Intro to JavaScript Lab

Lab Objectives

• Practice using data types, variables, operators, and conditionals in JavaScript
• Practice writing and calling JavaScript functions

Gradebook

Your task is to create a gradebook in JavaScript.

Setup

• Fork this repl in Replit.
• Write all code in the script.js file.
• To run your code, open the Shell tool (similar to the console) and type node script.js.
  • If you receive an error / prompt to select a version of node to install, press Enter to select the first option. Then type node script.js again.

Iteration 1

• Create two local variables: firstName and lastName.
• Write a function that returns the student’s initials with the . character after each initial. For example:
• Example:
  • firstName: Zoe, lastName: Ferrell
  • output: Z.F.

The program should display the initials from the main function using console.log().

Iteration 2

• Create a local array variable: scores.
• Write a function that returns the average of the scores in the array.
• Example:
  • grades: 85, 92, 84, 88
  • output: 87.25

The program should display the average score from the main function using console.log(). The average should display with exactly two decimal places.

Iteration 3

• Write a function that returns the letter grade based on the average score from Iteration 2.
• The grading scale is based on a 10-point scale:
  • A => 90 and above
  • B => 80 and above but less than 90
  • C => 70 and above but less than 80
  • D => 60 and above but less than 70
  • F => less than 60
• Example:
  • average: 87.25
  • output: B

The program should display the letter grade from the main function using console.log().

Iteration 4

*Refactor the function from Iteration 2 to meet the following criteria:

• The minimum score is 0.
• The maximum score is 100.
• Invalid scores should not be included in the calculation for the average score.
• Example:
  • grades: 85, -20, 92, 135, 84, 88, 40
  • scores excluded: -20, 135
  • average: 77.80 C

The program should display the average score from the main function using console.log(). The average should display with exactly two decimal places.

Spicy Challenges

Challenge 1

• Refactor the function from Iteration 4 to meet the following criteria:
  • If the student has 5 or more valid scores, the minimum score should be dropped and the remaining scores are used to calculate the average score and determine the letter grade.
• Example 1:
  • grades: 85, 92, 65, 84, 88
  • dropped score: 65
  • average: 87.25 B
• Example 2:
  • grades: 85, 92, 65, 84
  • dropped score: n/a (less than 5 scores)
  • average: 82.5 B

The program should display the average score from the main function using console.log(). The average should display with exactly two decimal places.

Challenge 2

• Write a function that meets the following criteria:
  • If the student has earned a grade other than an A, return the minimum score (as an integer) the student would have to earn on the next assignment that would bring their average to the next higher letter grade.
  • The new score may be above 100, the highest valid score. Return it anyway.
  • If the student already has an A, return any score that keeps the student at an A.
• Example 1:
  • grades: 75, 81, 90, 68
  • average: 78.50 C
  • new score: 86 (new average would be 80.00 B)
• Example 2:
  • grades: 85, 92, 84, 88
  • average: 87.25 B
  • new score: 101 (new average would be 90.00 A)