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JavaScript JavaScript Array Iteration Methods Combining Array Methods Nested Data and Additional Exploration

Posted by Tony Brackins
Tony Brackins
28,766 Points

Nested Data Challenge

I got it right. It worked.

However, I don't feel like I did it elegantly.

Please see my answer:

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"]
    }
  }
];

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


let hobbies;

hobbies = customers.reduce((bucket, customer)=>{

  let eachHobbie = customer.personal.hobbies.map((hobby)=>{

    return hobby
  })
  return bucket.concat(eachHobbie)
},[]);
Michael Kristensen
.a{fill-rule:evenodd;}techdegree seal-36
Michael Kristensen
Full Stack JavaScript Techdegree Graduate 26,251 Points

While the solution Steven Parker suggested, is definitely the more streamlines version, I think the solution that this chain of videos was trying to lead us to was: 

hobbies = customers
  .map(customer => customer.personal)
    .map(personal => personal.hobbies)
      .map(hobby => hobby)
  .reduce((arr, innerHobbies) => [...arr, ...innerHobbies], []);

Where you use .map() to iterate through the different layers, and then .reduce() the returned arrays.

1 Answer

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

You're doing a bit of extra work using "map" and the intermediate variable, you can simplify it down to just this:

hobbies = customers.reduce((bucket, customer) => bucket.concat(customer.personal.hobbies), []);
Tony Brackins
Tony Brackins
28,766 Points

Perfect. thx!!