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JavaScript JavaScript Array Iteration Methods Combining Array Methods Nested Data

The reduce method and the nested methods confused me the most in the entire course. I am stuck on the last challenge.

in the console I keep getting item is not iterable... hobbies = customers.reduce((accumulator, currentValue) => [...accumulator, ...currentValue.hobbies]);

app.js
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

hobbies = customers.reduce((accumulator, currentValue) => [...accumulator, ...currentValue.hobbies]);

2 Answers

Steven Parker
Steven Parker
231,269 Points

Oddly, I got a different error message: "Bummer: accumulator[Symbol.iterator] is not a function". But your error makes more sense, as a "customer" object isn't iterable (and so the spread operator won't work on it).

But you're really close. I see two issues:

  • the "reduce" function needs a second argument to initialize the accumulator as an empty array
  • the "customer" object has no "hobbies" property — but it has a "personal" which has a "hobbies"
Hermanos Solis Utrilla
Hermanos Solis Utrilla
18,184 Points

Hope this works for you:

hobbies = customers.map(customer => customer.personal)
                        .reduce((accum, current) => [...accum, ...current.hobbies], []);
Steven Parker
Steven Parker
231,269 Points

:warning: FYI: Explicit answers without any explanation are strongly discouraged by Treehouse and may be redacted by moderators