Functional Programming: Use the reduce Method to Anaylze

Tell us what’s happening:

Try my solution and the output give an error of “Infinity”. Then I tried FCC solution 1 answer and still give an error of “Infinity”. if the code runs correctly, the getRating(watchList) should give an answer of 8.675. I am not sure if this is a bug issue. Please kindly advise.

Kind regards,


Your code so far


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Challenge: Use the reduce Method to Analyze Data

Link to the challenge:

The solutions both work correctly for me.

Can you post the code that fails?

function getRating(watchList) {

  let nolanMovies = watchList.filter(movie => movie.Director === "Christopher Nolan");

  let nolanMovieRatingTotal = nolanMovies.reduce((total, movie) => {

    total += parseFloat(movie.imdbRating); // parseFloat() convert string to number

    return total;

  }, 0) 

  let nolanMovieCount = nolanMovies.length;

  let averageRating = nolanMovieRatingTotal / nolanMovieCount;

  return averageRating;


I did the long way. any suggestions to refactor it to cleaner code or errors in my logic.

I tried restart my login on the google chrome browser into FCC site and reset the coding exercise. It seems to work again for now.

1 Like

You can skip some variables and directly return the result of dividing what reduce returns with the filtered array length. But doing so makes it less obvious what is being returned as opposed to having a variable named averageRating.

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