Скачать или смотреть Get Unique Values from Object Arrays in JavaScript with Set

Learn how to extract unique values from a specific column in an array of objects in JavaScript using the `Set` method.
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Extracting Unique Values from Object Arrays in JavaScript

When working with arrays of objects in JavaScript, there are often situations where you want to extract unique values from a specific property. For instance, if you have an array representing products, you might want to obtain a unique list of sizes, colors, or any other attribute. This is a common problem among developers, and today, we will walk through a tidy solution using the Set object.

The Problem

Consider the following array of product objects:

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From this array, you want to extract the unique sizes available. The challenge is to ensure that you receive only distinct values—in this case, 'small' and 'large'—rather than multiple entries of the same size.

The Solution

To achieve this, we can utilize the concept of Set provided by JavaScript. The Set object allows you to store unique values of any type, whether primitive values or object references. Here’s how you can do it in a few easy steps:

Step 1: Map to Extract Sizes

First, we must transform the array of objects into an array of sizes. We can accomplish this using the .map() method:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Create a Set from Sizes

Next, wrap the array of sizes in a Set, which automatically removes duplicate values:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Convert the Set Back to an Array

Finally, to convert the Set back to an array, you can use the spread operator (...):

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Full Example Code

Here is everything put together in one comprehensive snippet:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Using the Set object in combination with the .map() function provides a straightforward and efficient way to extract unique values from an array of objects based on a specified property. Remember, this method is not limited to sizes; you can use the same approach to get unique values from any property, such as colors or weights, by just adjusting the map method.

Happy coding!