Get remaining time in a Teachable course

main.js

// I created this for (and tested it on) a learn.cantrill.io course 
// to quickly determine how much more video I have left to finish the course, 
// so I could plan my time in advance of an AWS exam.


function getTotalMinutesLeftInCourse() {
  let totalMinutes = 0;
  for (const chapter of getChapters()) {
    if (!chapterIsComplete(chapter)) {
      const [minutes, seconds] = getMinutesAndSeconds(getLengthString(chapter.innerText))
      totalMinutes += (minutes + (seconds / 60))
    }
  }
  return totalMinutes
}

function getChapters() {
  return document.querySelectorAll(".title-container");
}

function chapterIsComplete(chapter) {
  return chapter.previousElementSibling.getAttribute("aria-label") === "Completed item"
}

function getLengthString(string) {
  const lengthString = string.match(/\d:\d\d/)
  if (lengthString == null) {
      // this only happens with quizzes, which is accurate
      console.log(string, 'no match for length');
      return "0:00"
  }
  return lengthString[0];
}

function getMinutesAndSeconds(lengthString) {
  let [minutes, seconds] = lengthString.split(":")
  return [parseInt(minutes), parseInt(seconds)]
}

function getChapterThisManyHoursFromWhereIAmCurrently(hours) {
  let totalMinutes = 0;
  for (const chapter of getChapters()) {
    if (!chapterIsComplete(chapter)) {
      const [minutes, seconds] = getMinutesAndSeconds(getLengthString(chapter.innerText))
      totalMinutes += (minutes + (seconds / 60))
      if (totalMinutes >= (hours * 60)) {
        return [totalMinutes, chapter.innerText]
      }
    }
  }
}

function howManyHoursUntilChapter(chapterNameSubstring) {
  let totalMinutes = 0;
  for (const chapter of getChapters()) {
    if (!chapterIsComplete(chapter)) {
      const chapterText = chapter.innerText;
      if (chapterText.includes(chapterNameSubstring)) {
          return totalMinutes / 60;
      }
      const [minutes, seconds] = getMinutesAndSeconds(getLengthString(chapterText));
      totalMinutes += (minutes + (seconds / 60));        
    }
  }
}