How Can I Efficiently Extract Unique Values from an Array of Objects in JavaScript?

Efficiently Extracting Distinct Values from an Array of Objects in JavaScript

In JavaScript, obtaining distinct values from an array of objects can be a common task. Consider the following scenario:

var array = [
  { name: "Joe", age: 17 },
  { name: "Bob", age: 17 },
  { name: "Carl", age: 35 }
];

// Desired Result: [17, 35]

To achieve this result, one approach is to iterate through the array and maintain a separate array to store distinct values. However, this method can be inefficient, especially for large arrays.

An alternative approach, available in ES6/ES2015 and later, utilizes the Set data structure. Sets provide a unique collection of values, so you can create a new Set from the array of objects' desired property:

const uniqueAges = [...new Set(array.map(item => item.age))];

This statement iterates through the array using the map() function to extract the age property from each object. It then creates a Set from the extracted values using the new Set() constructor. Finally, it spreads the Set into an array using the spread operator (...), resulting in the desired list of distinct ages: [17, 35].

This approach offers significant performance benefits compared to the iterative method, especially for large datasets. It eliminates the need for additional data structures and minimizes the number of iterations required.

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