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Discover how to efficiently filter an array of objects in JavaScript by checking for the existence of specific properties. Learn with step-by-step instructions and examples!
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How to Filter an Array of Objects in JavaScript Based on Properties

When working with arrays of objects in JavaScript, you may encounter situations where you need to filter the array based on specific criteria, such as checking for the presence of a certain property within those objects. In this post, we will explore how to achieve this by using the case of filtering a cryptoData array to only include items that have a DISPLAY property.

The Problem

Suppose you have an array named cryptoData that consists of multiple objects, each representing data for different cryptocurrencies. Your goal is to create a new array containing only those objects that possess a specific property called DISPLAY. If an object in cryptoData does not contain this property, you want to remove it from the new array.

Here's a simplified representation of your dataset:

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

In the example above, only the nodes with the DISPLAY property should be included in the filtered array.

The Initial Attempt

Your initial code might look something like this:

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

However, this code is incorrect because it attempts to directly compare the properties of the objects in the array with a string, which will not work.

The Solution

To successfully filter the array based on whether each object contains the DISPLAY property, you can leverage the hasOwnProperty method. This method checks if the specific property exists within the object. Here's how you can implement the solution:

Step 1: Use the filter Method

Start by calling the filter method on the array, which allows you to iterate through each object.

Step 2: Implement hasOwnProperty

Next, for each object in the array, use the hasOwnProperty method to determine if the DISPLAY property exists.

Here’s the corrected code:

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

Explanation of the Code:

cryptoData.filter: This function goes through each item (or object) in the cryptoData array.

el.hasOwnProperty('DISPLAY'): For each object (el), this checks if the DISPLAY property exists.

Result: Only those objects containing the DISPLAY property will be kept in the filterdArray.

Step 3: Update the State

Finally, you update your component's state with the newly filtered array, making it available for rendering.

Conclusion

Filtering an array of objects to ensure only those with certain properties remain can be quite simple with the use of the filter method combined with hasOwnProperty. By applying this technique correctly, you can manage your data effectively and ensure that you're working only with the relevant information.

Now you can use this strategy in your own projects whenever you need to filter arrays of objects based on specific criteria. Happy coding!