Summary  
This chapter covers combining arrays, objects, and functions to process and transform collections of data by filtering objects based on their properties.  

General domain of usage  
User profile filtering

Combining **arrays**, **objects**, and **functions** allows you to build flexible and powerful solutions to many real-world challenges. Arrays help you store and manage lists of data, while objects let you organize related information together. Functions provide the logic to process, transform, and analyze your data. By integrating these building blocks, you can solve practical problems such as searching, filtering, or transforming collections of complex data like user profiles, product lists, or event records.

// Function to filter users by age and return only those who are 18 or older
function getAdults(users) {
  return users.filter(function (user) {
    return user.age >= 18;
  });
}

const users = [
  { name: "Alice", age: 17 },
  { name: "Bob", age: 22 },
  { name: "Carol", age: 19 },
  { name: "Dave", age: 15 }
];

const adults = getAdults(users);
console.log(JSON.stringify(adults)); // Output: [{"name":"Bob","age":22},{"name":"Carol","age":19}]

**Step-by-step explanation ofiltering users by age.**

1. The `users` array contains several objects, each representing a user with a `name` and an `age` property;
2. The `getAdults` function takes the `users` array as its argument;
3. Inside `getAdults`, the `filter` method is used to create a new array by checking each user object;
4. The filtering function checks if the `age` property of each user is greater than or equal to 18;
5. Only users who meet this condition are included in the new array;
6. The result is stored in the `adults` variable, which contains only users who are 18 or older;
7. When you log `adults`, you see an array with objects for "Bob" and "Carol", because their ages are 22 and 19, meeting the age requirement.

Lær hvordan du kontrollerer programlogikk, strukturerer data og bygger dynamiske funksjoner ved hjelp av JavaScript. Arbeid med funksjoner, arrayer, objekter og løkker, og bruk deretter disse ferdighetene til å lage et interaktivt profilsystem. Få kjernekompetansen som trengs for å gå videre til React og moderne frontend-utvikling.

Bruk kunnskapen din i et miniprosjekt, lær grunnleggende feilsøking, og forbered deg på neste steg i JavaScript.

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