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JavaScript JavaScript Array Iteration Methods Combining Array Methods Nested Data

Samuel Fortunato
Samuel Fortunato
20,229 Points

JavaScript Array Iteration Methods Last Exercise = Stumped

The last exercise in this course has got me.

const customers = [
  {
    name: "Tyrone",
    personal: {
      age: 33,
      hobbies: ["Bicycling", "Camping"]
    }
  },
  {
    name: "Elizabeth",
    personal: {
      age: 25,
      hobbies: ["Guitar", "Reading", "Gardening"]
    }
  },
  {
    name: "Penny",
    personal: {
      age: 36,
      hobbies: ["Comics", "Chess", "Legos"]
    }
  }
];

let hobbies;

// hobbies should be: ["Bicycling", "Camping", "Guitar", "Reading", "Gardening", "Comics", "Chess", "Legos"]
// Write your code below

This is what I have so far:

hobbies = customers
  .reduce((hobbiesList, customer) => customer.personal.hobbies.map(hobby => hobby));

Not working. Don't get it. :(

1 Answer

Steven Parker
Steven Parker
229,788 Points

You seem to be heading in the right direction. Here's a few hints:

  • that "map" function isn't doing anything, you can remove it entirely
  • you might need to give "reduce" an additional argument for an initial value
  • the function needs to use both arguments
  • the function should do something that combines two arrays together into one
Samuel Fortunato
Samuel Fortunato
20,229 Points

Ok, I've gotten farther. My code is now this:

hobbies = customers
  .reduce((hobbiesList, customer) => hobbiesList + customer.personal.hobbies, []);

And my output is now this, according to the code challenge:

"Bicycling,CampingGuitar,Reading,GardeningComics,Chess,Legos"

Seems like I just have to get each array item individually and not grab the whole thing? Why isn't reduce() grabbing each array item individually? I thought that's what it did?

Steven Parker
Steven Parker
229,788 Points

You're really close now! You're successfully combining all the individual hobbies into a string, so now you only need to change it so that the combination is another array. Hint: the "spread" operator ("...") might be useful.