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JavaScript JavaScript Array Iteration Methods Array Manipulation Practice filter()

how do I properly return this new array?

need help with this challenge. I've gotten this far but I definitely know something isn't quite right with my return statement, do I need to use [] at all there?

app.js
const years = [1989, 2015, 2000, 1999, 2013, 1973, 2012];
let century20;

// century20 should be: [1989, 2000, 1999, 1973]
// Write your code below
 century20 = years.filter (year => {
  if (year.index <= 2000) {
    return century20[year];
  } 
 });

console.log(century20);

1 Answer

Emmanuel C
Emmanuel C
10,636 Points

Hey Cole,

So, filter takes a function as a parameter that is applied to each item in the array. When you create the arrow function with year as a parameter. year is the item in the years array. So doing year.index would be like doing 1989.index, in the first iteration.

Also, what returns from that inner function should be a boolean(true/false) as to whether that year item passes the condition it's supposed to be filtered by. Basically, just checking and returning if the year <= 2000 is what that inner function is supposed to do. Something like this...

 century20 = years.filter(year => { return (year <= 2000) });

You can shorten is further with arrow functions by removing the curly braces, the return, and the parenthesis too if you'd like. Like...

 century20 = years.filter(year => year <= 2000);

alright this makes sense now, my code was saying to iterate down from 2000 not the whole list. thanks for the help!