Скачать или смотреть How to Add Object Key After Comparing Two Arrays of Objects in JavaScript

Learn a cleaner approach to add an `isSupported` key for each country in your array by comparing two arrays of country objects in JavaScript.
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How to Add Object Key After Comparing Two Arrays of Objects in JavaScript

In the world of programming, especially when dealing with data structures like arrays, it's common to need to combine or compare data. One frequent scenario developers encounter is the need to compare two arrays of objects and then add a property to these objects based on the comparison results. In this guide, we'll delve into an example involving countries and demonstrate a more efficient way to achieve this in JavaScript.

The Problem

Imagine you have two arrays of country objects. The first array, allCountries, contains a list of all available countries along with their details such as name, code, alpha-3 code, and numeric code:

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

The second array, supportedCountries, represents a subset of the first array that details which countries are supported:

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

Your task is to create a new array that contains all the countries from allCountries, but with an additional property isSupported set to true for supported countries and false for non-supported countries.

The Initial Solution

One approach might look like this:

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

While this solution works, there is a more elegant and cleaner way to achieve the same result.

A Cleaner Approach

Using the map method in combination with the find method allows us to simplify the process and avoid the need for nested loops. Here's how it can be done:

Step-by-Step Solution

Map Over allCountries: Use the map function to iterate over allCountries, which will allow us to create a new array with our desired modifications.

Check for Support: Use the find method to see if the current country exists in the supportedCountries array. The use of !! converts the result into a boolean (true or false).

Build the Result: Return a new object for each country that includes all existing properties, along with the isSupported value.

The Code

Here’s how the final, cleaner code looks:

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

Conclusion

In summary, when comparing arrays and adding properties based on certain conditions, using modern JavaScript methods like map and find not only makes your code cleaner and more readable but also improves its efficiency. This way, you can easily manage larger datasets without running into performance issues that arise from nested loops.

Now that you've learned how to compare two arrays of objects and add a key in a clearer way, feel free to apply this technique to your own projects and simplify your data management!