HELP! Functional Programming: Use the reduce Method to Analyze Data

Where have I gone wrong?
I didn’t want to write everything in a single line like the hint solution.So, I separated everything into different functions and variables. But, there seems to be a problem which I am not able to figure out.

P.S- this is the hint soln.

var averageRating = watchList.filter(x => x.Director === "Christopher Nolan").map(x => Number(x.imdbRating)).reduce((x1, x2) => x1 + x2) / watchList.filter(x => x.Director === "Christopher Nolan").length;

I have understood the concept. It’s just that, I want to know why my code is wrong.
Thanks!

// the global variable
var watchList = [
{
“Title”: “Inception”,
“Year”: “2010”,
“Rated”: “PG-13”,
“Released”: “16 Jul 2010”,
“Runtime”: “148 min”,
“Genre”: “Action, Adventure, Crime”,
“Director”: “Christopher Nolan”,
“Writer”: “Christopher Nolan”,
“Actors”: “Leonardo DiCaprio, Joseph Gordon-Levitt, Ellen Page, Tom Hardy”,
“Plot”: “A thief, who steals corporate secrets through use of dream-sharing technology, is given the inverse task of planting an idea into the mind of a CEO.”,
“Language”: “English, Japanese, French”,
“Country”: “USA, UK”,
“Awards”: “Won 4 Oscars. Another 143 wins & 198 nominations.”,
“Poster”: “http://ia.media-imdb.com/images/M/MV5BMjAxMzY3NjcxNF5BMl5BanBnXkFtZTcwNTI5OTM0Mw@@._V1_SX300.jpg”,
“Metascore”: “74”,
“imdbRating”: “8.8”,
“imdbVotes”: “1,446,708”,
“imdbID”: “tt1375666”,
“Type”: “movie”,
“Response”: “True”
},
{
“Title”: “Interstellar”,
“Year”: “2014”,
“Rated”: “PG-13”,
“Released”: “07 Nov 2014”,
“Runtime”: “169 min”,
“Genre”: “Adventure, Drama, Sci-Fi”,
“Director”: “Christopher Nolan”,
“Writer”: “Jonathan Nolan, Christopher Nolan”,
“Actors”: “Ellen Burstyn, Matthew McConaughey, Mackenzie Foy, John Lithgow”,
“Plot”: “A team of explorers travel through a wormhole in space in an attempt to ensure humanity’s survival.”,
“Language”: “English”,
“Country”: “USA, UK”,
“Awards”: “Won 1 Oscar. Another 39 wins & 132 nominations.”,
“Poster”: “http://ia.media-imdb.com/images/M/MV5BMjIxNTU4MzY4MF5BMl5BanBnXkFtZTgwMzM4ODI3MjE@._V1_SX300.jpg”,
“Metascore”: “74”,
“imdbRating”: “8.6”,
“imdbVotes”: “910,366”,
“imdbID”: “tt0816692”,
“Type”: “movie”,
“Response”: “True”
},
{
“Title”: “The Dark Knight”,
“Year”: “2008”,
“Rated”: “PG-13”,
“Released”: “18 Jul 2008”,
“Runtime”: “152 min”,
“Genre”: “Action, Adventure, Crime”,
“Director”: “Christopher Nolan”,
“Writer”: “Jonathan Nolan (screenplay), Christopher Nolan (screenplay), Christopher Nolan (story), David S. Goyer (story), Bob Kane (characters)”,
“Actors”: “Christian Bale, Heath Ledger, Aaron Eckhart, Michael Caine”,
“Plot”: “When the menace known as the Joker wreaks havoc and chaos on the people of Gotham, the caped crusader must come to terms with one of the greatest psychological tests of his ability to fight injustice.”,
“Language”: “English, Mandarin”,
“Country”: “USA, UK”,
“Awards”: “Won 2 Oscars. Another 146 wins & 142 nominations.”,
“Poster”: “http://ia.media-imdb.com/images/M/MV5BMTMxNTMwODM0NF5BMl5BanBnXkFtZTcwODAyMTk2Mw@@._V1_SX300.jpg”,
“Metascore”: “82”,
“imdbRating”: “9.0”,
“imdbVotes”: “1,652,832”,
“imdbID”: “tt0468569”,
“Type”: “movie”,
“Response”: “True”
},
{
“Title”: “Batman Begins”,
“Year”: “2005”,
“Rated”: “PG-13”,
“Released”: “15 Jun 2005”,
“Runtime”: “140 min”,
“Genre”: “Action, Adventure”,
“Director”: “Christopher Nolan”,
“Writer”: “Bob Kane (characters), David S. Goyer (story), Christopher Nolan (screenplay), David S. Goyer (screenplay)”,
“Actors”: “Christian Bale, Michael Caine, Liam Neeson, Katie Holmes”,
“Plot”: “After training with his mentor, Batman begins his fight to free crime-ridden Gotham City from the corruption that Scarecrow and the League of Shadows have cast upon it.”,
“Language”: “English, Urdu, Mandarin”,
“Country”: “USA, UK”,
“Awards”: “Nominated for 1 Oscar. Another 15 wins & 66 nominations.”,
“Poster”: “http://ia.media-imdb.com/images/M/MV5BNTM3OTc0MzM2OV5BMl5BanBnXkFtZTYwNzUwMTI3._V1_SX300.jpg”,
“Metascore”: “70”,
“imdbRating”: “8.3”,
“imdbVotes”: “972,584”,
“imdbID”: “tt0372784”,
“Type”: “movie”,
“Response”: “True”
},
{
“Title”: “Avatar”,
“Year”: “2009”,
“Rated”: “PG-13”,
“Released”: “18 Dec 2009”,
“Runtime”: “162 min”,
“Genre”: “Action, Adventure, Fantasy”,
“Director”: “James Cameron”,
“Writer”: “James Cameron”,
“Actors”: “Sam Worthington, Zoe Saldana, Sigourney Weaver, Stephen Lang”,
“Plot”: “A paraplegic marine dispatched to the moon Pandora on a unique mission becomes torn between following his orders and protecting the world he feels is his home.”,
“Language”: “English, Spanish”,
“Country”: “USA, UK”,
“Awards”: “Won 3 Oscars. Another 80 wins & 121 nominations.”,
“Poster”: “http://ia.media-imdb.com/images/M/MV5BMTYwOTEwNjAzMl5BMl5BanBnXkFtZTcwODc5MTUwMw@@._V1_SX300.jpg”,
“Metascore”: “83”,
“imdbRating”: “7.9”,
“imdbVotes”: “876,575”,
“imdbID”: “tt0499549”,
“Type”: “movie”,
“Response”: “True”
}
];

// Add your code below this line
var A = function a(x){
x.Director === “Christopher Nolan”;
}
function b(x){
return x.imdbRating;
}
var averageRating = A.map(b)
.reduce((x1,x2)==(x1+x2)/watchList.filter(A.length));

// Add your code above this line

console.log(averageRating);

because ur syntax in this line

.reduce((x1,x2)==(x1+x2)/watchList.filter(A.length));

is not correct.

go to mdn reduce, and you see there explained how to write reduce
also, reduce is imo one of the tuffest. might also wanna check a yt video or something.

I changed the syntax. Also, I found out that I hadn’t converted the imdb rating to number. So, I did that as well. But, It still shows error.
The error is A.map isn’t a function

map is an array function

maybe log A before you try to call it. then, you can see what A is.
prob not an array

This function make so that A returns always undefined, it needs to return something, if it doesn’t return, it is undefined.

A is a function that returns undefined, or if you fix it a Boolean, it doesn’t have a length property.you want to do watchList.filter(...).length

Same as before, A is not an array, it is a function.

Probably there is more.

Try to apply rubber duck debugging, explain your code step by step to someone that doesn’t know how to code, so you need to explain what each variable, each statement, each method does and how it works.
You can also explain it here, adding comments to your code, and we will try to help

Okay, I understood two things -
one is that I can’t equate var A to function a, as that would result in A becoming a function.
two is that I have to return an array, and then map the returned array to function b, instead what I’ve done is I have mapped A(which is a function) to b.

Am I right?

You can equate A to a function but then you can’t use it that way…
b is a function that you have used as callback of the map method, so map will return an array in which all elements are the elements of the original array changed using the callback function