Student record search challenge - Extra credit challenge

Question

So I'm struggling with one of the extra credit challenges from the Javascript course. The idea is to add an additional message when the student is not in the array of objects "students", rather than simply doing nothing.

I spent a while trying to figure out how I can use if/else/else if statements, but when they're nested I find it very confusing.

My initial idea was to test whether or not the student was in the list by using the indexOf function and comparing it to see if it was more than -1, and then have the rest of the program run if that was true. However, it seems to print the message even if the student is in the list of students.

Additionally after much frustration and iterations I can't seem to remember how I tried to implement that and have ended up with the code below in which I've tacked on the code I'm trying to make check if the student is there or not. I think both attempts ended up with the same result.

I have a feeling that somehow I have accidentally made the initial condition of checking whether they are in the list of students always true somehow, but I don't know why or how I've done that.

var message = '';
var student;
var search;


function print(message) {
  var outputDiv = document.getElementById('output');
  outputDiv.innerHTML = message;
}

function getStudentReport( student ) {
  var report = '<h2>Student: ' + student.name + '</h2>';
  report += '<p>Track: ' + student.track + '</p>';
  report += '<p>Points: ' + student.points + '</p>';
  report += '<p>Achievements: ' + student.achievements + '</p>';
  return report;
}


while (true) {
  search = prompt("Please enter the name of a student e.g. 'Judy' to find information about that student. When you're finished type 'quit' to exit");
  if (search === null || search.toLowerCase() === "quit") {
    break;
  } else {
     for (var i = 0; i < students.length; i += 1) {
      student = students[i];
      if ( student.name === search ) {
        message = getStudentReport( student );
        print(message);
      } else {
          if (students.indexOf(search) === -1) {
            print(search + " ain't here.");
        }
      }
    }
  }
}

Answer 1 · 2019-01-19T22:22:02Z

January 19, 2019 10:22pm

The first thing that should help in making your nested statements easier to understand is that your first else clause isn't needed in this case:

if (search === null || search.toLowerCase() === "quit") {
    break;
} else {

The first condition being tested will break out of the loop completely if search is equal to null or "quit", so therefore any other values will cause the loop to continue. In my opinion it's cleaner to remove the else completely to avoid any unnecessary nesting. As in:

if (search === null || search.toLowerCase() === "quit") {
    break;
}
for (var i = 0; i < students.length; i += 1) {
    ...

For your searching strategy, using the indexOf() function is going to cause some problems because of the data structure being used for students. students is an array of objects and those objects in turn have both strings and numbers. By using the call of students.indexOf(search), you are trying to search for a string element (search) in the students array. Since all of the elements in the array are objects and not strings, the value is always going to come up as -1.

You may also want to ask yourself if that search is needed at all. You're already checking if the student exists:

if ( student.name === search )

If that condition is true, then the student exists and if it's false, then the for loop should continue on through the rest of the student records and check if any of those are a match. You won't know if the student exists or not until each record is checked.

Hopefully that makes sense and helps a bit.

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Sam Morpeth

Sam Morpeth

Student record search challenge - Extra credit challenge

1 Answer

Jon Boettcher

Jon Boettcher