Assignment #2: Scrabble Scorer

For your second assignment, we'll ask you to modify and improve our Scrabble Scorer program. Did you think you were going to work on Mars Rover code already? That will come next!

We want you to update our program that asks a user for a word and outputs a score. Your final version will have three scoring algorithms and allow a user to interactively choose which algorithm to use. We've provided some starter code that includes the official Scrabble scoring point system and we'd like you to make some modifications to improve it.

Let's roll.

Requirements

Note

The requirements below are what your assignment should look like when it's time to submit. Rome wasn't built in a day and neither was Scrabble.

This assignment is broken down so you can complete small pieces as you go. You need to move sequentially starting with Part A below. You'll have a much more enjoyable time writing this program if you read this entire page before even opening repl.it.

  1. Write an initialPrompt() function that asks a user to input a word.
  2. Have the program return a score for the word using oldScrabbleScorer().
  3. Add additional scoring algorithms and store them in the scoringAlgorithms array.
  4. Create a transform() function that takes in the oldPointStructure object and returns a newPointStructure object.
  5. Use the runProgram() function to serve as the starting point for your program.

Starter Code

Fork this replit.

You only need to pay attention to one file here, scrabble-scorer.js. Within this JavaScript file is still some more starter code that you don't need to touch. We'll point out what you should be modifying here to write your Scrabble Scorer program.

Hit the repl.it run button initially and you'll see a message printed to the console:

> node index
Let's play some Scrabble!
>

Tip

If you don't see this message printed and have exhausted your troubleshooting skills, reach out to your classmates or course staff ASAP so you can get started with the real coding.

Instructions

A) Initial Prompt

  1. Modify the provided initialPrompt() function to prompt the user to enter a word to score.
  2. Use the oldScrabbleScorer() function provided to score the word provided by the user. Print the result to the console.

Before you move on, be sure you're on the right track. At this point, your program should have an output like this:

> node index
Let's play some Scrabble!

Enter a word to score: pineapple
Points for 'P': 3
Points for 'I': 1
Points for 'N': 1
Points for 'E': 1
Points for 'A': 1
Points for 'P': 3
Points for 'P': 3
Points for 'L': 1
Points for 'E': 1

>

B) Add and Organize Scoring Algorithms

Your job here is to write two other scoring algorithms for the Scrabble player.

  1. simpleScore: Define a function that takes a word as a parameter and returns a numerical score. Each letter within the word is worth 1 point.
  2. vowelBonusScore: Define a function that takes a word as a parameter and returns a score. Each vowel within the word is worth 3 points, and each consonant is worth 1 point.

Note

Make each scoring algorithm case insensitive, meaning that they should all ignore case when assigning points.

Once you've written these scoring functions, organize all three of the scoring options into an array. Your program will use the scoringAlgorithms array to retrieve information about the three scoring algorithms and convey that information to the user.

  1. Finish writing the scoringAlgorithms array. It should be populated with three objects, one for each of the three scoring options. Each object should contain three keys: name, description, and scoringFunction.

  2. Examine the table for the information to store in name and description. The scoringFunction for each object should be the name of one of the three scoring algorithms already defined.

    Name Description Score Function
    Simple Score Each letter is worth 1 point. A function with a parameter for user input that returns a score.
    Bonus Vowels Vowels are 3 pts, consonants are 1 pt. A function that returns a score based on the number of vowels and consonants.
    Scrabble The traditional scoring algorithm. Uses the oldScrabbleScorer() function to determine the score for a given word.
  3. Finish writing scorerPrompt() so that the user can select which scoring algorithm to use when the program scores their word. Use the selected algorithm to determine the score for the word:

    1. If the user enters 0, have the program output a score using the simple scorer.
    2. If the user enters 1, use the vowel bonus scoring function.
    3. If the user enters 2, use the Scrabble scoring option.

    scorerPrompt() should return the object the user has selected.

    Tips

    Your scoringAlgorithms structure now holds all of the scoring information required for the program.

    To access a scoring object and its properties, use a combination of bracket notation and dot notation.

    Examples

    // Simple scoring
    console.log("algorithm name: ", scoringAlgorithms[0].name);
    console.log("scoringFunction result: ", scoringAlgorithms[0].scoringFunction("JavaScript"));
    

    Console Output

    algorithm name:  Simple Score
    scoringFunction result:  10
    
  4. Call scorerPrompt() inside of runProgram() so that the program asks the user for a scoring algorithm after prompting for a word. Use the scoring object returned from scorerPrompt() to score the user's word and let the user know what score their word receives.

Before moving forward, your running program should behave roughly like this:

> node index
Let's play some Scrabble!

Enter a word to score: coconut
Which scoring algorithm would you like to use?

0 - Simple: One point per character
1 - Vowel Bonus: Vowels are worth 3 points
2 - Scrabble: Uses scrabble point system
Enter 0, 1, or 2: 0
Score for 'coconut': 7

>

C) Transform Scrabble Scoring

Currently, the software contains the data structure below for the traditional Scrabble scoring algorithm. Take a few moments to review how the oldPointStructure object relates a point value to a letter.

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const oldPointStructure = {
   1: ['A', 'E', 'I', 'O', 'U', 'L', 'N', 'R', 'S', 'T'],
   2: ['D', 'G'],
   3: ['B', 'C', 'M', 'P'],
   4: ['F', 'H', 'V', 'W', 'Y'],
   5: ['K'],
   8: ['J', 'X'],
   10: ['Q', 'Z']
};

The keys of oldPointStructure are the Scrabble points, and the values are arrays of letters. All letters in the array have the Scrabble point value equal to the key. For example, 'A' and 'R' are worth 1, 'K' is worth 5, and 'J' is worth 8.

To find the point value for a letter with the old format, the program must iterate over each key in oldPointStructure and then check if the letter is inside the array paired with that key. This search within a search is inefficient.

Tip

Think about this for a second. The scoring action takes in letters in a word as input and outputs numerical point values.

We can improve our program by rewriting the data structure to better fit the action we want to take. Keep this idea in mind as you go on to code your own applications.

It would improve the performance of the program to create a newPointStructure object that has 26 keys, one for each letter. The value of each key will be the Scrabble point value.

Examples of the new key storage:

  • a is worth 1
  • b is worth 3
  • c is worth 3
  • j is worth 8

In newPointStructure, the letters themselves are keys, so a single search will identify a point value.

Example

Example of newPointStructure object usage.

console.log("Scrabble scoring values for");
console.log("letter a: ", newPointStructure.a);
console.log("letter j: ", newPointStructure.j);
console.log("letter z: ", newPointStructure["z"]);

Console Output

Scrabble scoring values for
letter a:  1
letter j:  8
letter z:  10

Transform the Object

  1. Write the rest of the transform() function. It will need to take an object as a parameter - specifically the oldPointStructure object. Calling transform(oldPointStructure) will return an object with lowercase letters as keys. The value for each key will be the points assigned to that letter.

    Tips

    1. Recall that for...in loops iterate over the keys within an object.

    2. If you need a reminder of how to assign new key/value pairs, review the relevant section in the Objects and Math chapter.

    3. To access the letter arrays within oldPointStructure, use bracket notation (oldPointStructure['key']).

    4. To access a particular element within a letter array, add a second set of brackets (oldPointStructure['key'][index]), or assign the array to a variable and use variableName[index].

      Examples

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      console.log("Letters with score '4':", oldPointStructure['4']);
      console.log("3rd letter within the key '4' array:", oldPointStructure['4'][2]);
      
      let letters = oldPointStructure['8'];
      console.log("Letters with score '8':", letters);
      console.log("2nd letter within the key '8' array:", letters[1]);
      

      Console Output

      Letters with score '4': [ 'F', 'H', 'V', 'W', 'Y' ]
      3rd letter within the key '4' array: V
      
      Letters with score '8': [ 'J', 'X' ]
      2nd letter within the key '8' array: X
      
  2. Locate the newPointStructure object in the starter code and set it equal to transform(oldPointStructure).

    Warning

    Hard-coding the newPointStructure object literal like this:

    let newPointStructure =
    {
       a:1,
       b: 1,
       c: 1,
       etc ...
    }
    

    won't pass. And you'll lose an opportunity to practice this skill.

  3. Once you've defined newPointStructure, use it to finish writing the scrabbleScore() function and then replace the oldScrabbleScorer() function in scoringAlgorithms with this new function.

    Tip

    oldScrabbleScorer() uses oldPointStructure and returns a score for each letter in a word. You'll want to write scrabbleScore() to use newPointStructure and return a cumulative score for the whole word entered.

Test Words

Here are some words you can use to test your code:

  1. JavaScript = 24 points using Scrabble, 10 using Simple Score, and 16 using Bonus Vowels.
  2. Scrabble = 14 points using Scrabble, 8 using Simple Score, and 12 using Bonus Vowels.
  3. Zox = 19 points using Scrabble, 3 using Simple Score, and 5 using Bonus Vowels.

Example Output

> node index
Let's play some Scrabble!

Enter a word to score: rum
Which scoring algorithm would you like to use?

0 - Simple: One point per character
1 - Vowel Bonus: Vowels are worth 3 points
2 - Scrabble: Uses scrabble point system
Enter 0, 1, or 2: 2
Score for 'rum': 5

>

Bonus Missions

  1. Currently, the prompts accept ANY input values. The user could enter something other than 0, 1, or 2 when selecting the scoring algorithm, and they could enter numbers or symbols when asked for a word. Modify your code to reject invalid inputs and then re-prompt the user for the correct information.
  2. Score words spelled with blank tiles by adding ' ' to the newPointStructure object. The point value for a blank tile is 0.