Teachable Course Length

teachable_course_length.js

const lessons = document.querySelectorAll('.lecture-name');

let durations = [];
lessons.forEach((lesson) => {
    const name = lesson.innerText;
    const start = name.indexOf("(");
    const end = name.indexOf(")");
    const time = name.substring(start + 1,end);
    
    if( time != '' && time != undefined && time.indexOf(":") > 0 ) {
        durations.push(time);
    }
});

console.log(formatDuration(sumDurations(durations)));

function sumDurations(durations) {
    return durations.reduce((sum, string) => {
      var mins, secs;
      [mins, secs] = string.split(":").slice(-2).map(n => parseInt(n, 10));
      return sum + mins * 60 + secs;
    }, 0);
  }
  
  function formatDuration(duration) {
    function pad(number) {
      return `${number}`.slice(-2);
    }
  
    let hours = duration / 3600 | 0;
    let minutes = duration % 3600 / 60 | 0;
    let seconds = duration % 60;
    let minsSecs = `${pad(minutes)}:${pad(seconds)}`;
  
    return hours > 0 ? `${hours}:${minsSecs}` : minsSecs;
  }

This is awesome