Find out how long you have spent watching videos at https://es6.io

index.js

const watched = document.querySelectorAll( '.video.completed' );
let totalSeconds = 0;

// Loop over each video watched.
watched.forEach( video => {
  let videoTime = video.querySelector( 'span.duration' ).textContent.split( ':' );

  // Turn minutes:seconds into just seconds and append to totalSeconds.
  videoTime.map( array => {
    totalSeconds += ( parseInt( array[0] ) * 60 ) + parseInt( array[1] );
  })
});

const secondsSaved = totalSeconds * (1.25 - 1);
const actualSecondsSpent = totalSeconds - secondsSaved;

// Convert seconds into hours:minutes:seconds.
function convertTime( secs ) {
  let convertedTime = {
    hours: Math.floor( secs / 3600 ),
    minutes: Math.floor( (secs % 3600) / 60 ),
    seconds: secs % 60
  };
  return `${convertedTime.hours}:${convertedTime.minutes}:${convertedTime.seconds}`;
}

console.clear();
console.log(`Watched video time is ${convertTime(totalSeconds)}`);
console.log(`You actually spent ${convertTime(actualSecondsSpent)}`);
console.log(`You saved ${convertTime(secondsSaved)}`);