Скачать или смотреть Extracting Image URLs from a GraphQL Object in Gatsby

Struggling to get the image URLs from a JavaScript object in Gatsby using GraphQL? Learn how to filter out non-existent images and access the URLs effortlessly.
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This video is based on the question https://stackoverflow.com/q/68892674/ asked by the user 'Shuib Abdillahi' ( https://stackoverflow.com/u/16515593/ ) and on the answer https://stackoverflow.com/a/68892734/ provided by the user 'Djave' ( https://stackoverflow.com/u/630203/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Extracting Image URLs from a GraphQL Object in Gatsby

If you're developing a blog website using Gatsby and GraphQL, you may run into an issue when trying to extract image URLs from a JavaScript object. You might find that the array contains both valid images and null values, which can complicate your mapping logic. In this guide, we will address this problem and walk you through a solution to efficiently extract the image URLs you need.

The Problem

You are trying to map over an array of objects that represent guides, each potentially containing an image. Here’s a snippet of what you might have tried:

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

The output reveals that the array consists of objects with a fluid property, where the image URL resides:

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

However, when you attempt to access the image source directly:

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

You encounter an error stating that “fluid is undefined.”

Why This Happens

The error arises because some entries in your array do not have an image object associated with them, thus leaving e.node.image as null. When you try accessing properties of null, you get the error.

The Solution

To solve this challenge, you can filter the entries to only include those with images before mapping them to extract the URLs. Let’s break this down step by step.

Step 1: Filter Out Null Entries

First, you want to filter the array to remove any entries that do not contain a valid image. You can achieve this with the following code:

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

Step 2: Map the Remaining Entries to Extract URLs

Once you have a clean array that only includes posts with valid images, you can then map over this filtered array to extract the image URLs:

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

Full Code Example

Combining these steps, your final code should look like this:

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

Conclusion

By filtering out null values before trying to access properties deeper in the object, you can efficiently extract the image URLs from your GraphQL objects in Gatsby. This approach will not only prevent errors but also simplify your data handling when dealing with variable entries.

Now that you have this technique, you can confidently access image sources in your projects, enhancing your blog website's functionality in no time. Happy coding!