Exercises: Modules

Practice makes better. You will create a project that accomplishes the following:

1. Steps through a list of Yes/No questions.
2. Calls functions based on the user’s responses.

Rather than coding all of the functions from scratch, you are going to use existing modules to help assemble your project.

The starter code for these exercises can be found within your javascript-projects/modules/exercises directory.

Export Finished Modules

Lucky you! Some of your teammates have already coded the necessary functions in the averages.js and display.js files.

1. In averages.js, add code to export all of the functions within an object.

   Check Your Solution

   module.exports = {
      averageForStudent: averageForStudent,
      averageForTest: averageForTest
   };

2. In display.js, add code to export ONLY printAll as a function.

Code & Export New Module

randomSelect.js requires your attention.

1. Add code to complete the randomFromArray function. It should take an array as an argument and then return a randomly selected element from that array.

   Check Your Solution

   function randomFromArray(arr){
      let index = Math.floor(Math.random()*arr.length);
      return arr[index];
   }

2. Do not forget to export the randomFromArray function so you can use it in your project.

Import Required Modules

The project code is in index.js. Start by importing the required modules:

1. Assign readline-sync to the input variable.

   Check Your Solution

   const input = require('readline-sync');

2. Assign the functions from averages.js to the averages variable.

3. Assign the printAll function from display.js to the printAll variable.

   Check Your Solution

   const printAll = require('./display.js');

4. Assign the function from randomSelect.js to the randomSelect variable.

Finish the Project

Now complete the project code. The comments in index.js will still show you where to add code for the following tasks:

1. Call printAll to display all of the tests and student scores. Be sure to pass in the correct arguments.

   Check Your Solution

   printAll(astronauts, testTitles, scores);

2. Using dot notation, call averageForTest to print the class average for each test. Use j and scores as arguments.

3. Call averageForStudent (with the proper arguments) to print each astronaut’s average score.

   Check Your Solution

   let avg = averages.averageForStudent(j, scores);

4. Call randomSelect to pick the next spacewalker from the astronauts array.

Sanity check!

Properly done, your output should look something like:

Console Output

Would you like to display all scores? Y/N: y
Name        Math      Fitness   Coding    Nav       Communication
Fox         95        86        83        81        76
Turtle      79        71        79        87        72
Cat         94        87        87        83        82
Hippo       99        77        91        79        80
Dog         96        95        99        82        70

Would you like to average the scores for each test? Y/N: y
Math test average = 92.6%.
Fitness test average = 83.2%.
Coding test average = 87.8%.
Nav test average = 82.4%.
Communication test average = 76%.

Would you like to average the scores for each astronaut? Y/N: y
Fox's test average = 84.2%.
Turtle's test average = 77.6%.
Cat's test average = 86.6%.
Hippo's test average = 85.2%.
Dog's test average = 88.4%.

Would you like to select the next spacewalker? Y/N: y
Turtle is the next spacewalker.