Скачать или смотреть How to Avoid Hard Coding Data Objects in Vue.js 3

Learn how to efficiently manage dynamic data objects in Vue.js 3 without hard coding values, especially when dealing with API responses and filtering.
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This video is based on the question https://stackoverflow.com/q/68756679/ asked by the user 'Dan' ( https://stackoverflow.com/u/7740650/ ) and on the answer https://stackoverflow.com/a/68757242/ provided by the user 'Vasile Radeanu' ( https://stackoverflow.com/u/13981886/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Avoid Hard Coding Data Objects in Vue.js 3

When working with Vue.js, especially when making API requests, one common problem developers face is how to effectively manage dynamic data without resorting to hard coding. Hard coding values into your data structure makes your code less flexible and more difficult to maintain. In this post, we'll explore a specific scenario surrounding this issue and provide a clear solution to manage your data objects dynamically.

Understanding the Problem

Imagine you're working on a Vue.js application where you're fetching data from an API using Axios. Suppose your API returns subjects categorized by year, and you want to allow users to filter these subjects based on their input. Here’s where the problem arises. You've defined a method to access the subjects, but at runtime, if the years you're attempting to access aren't predefined, you encounter an error:

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This error occurs because you're trying to access a property on this.source.subjects for a year that doesn't exist in the data. For developers, hard coding these years into the data object seems like a quick fix, but it’s not a robust solution.

The Solution: Dynamic Data Management

To avoid hard coding data values, we'll utilize optional chaining in JavaScript. This allows us to safely access properties without throwing an error if they are undefined. Here’s how to implement this approach in your Vue.js component.

Step 1: Fetch Data Dynamically

When you fetch the data from the API, ensure your created lifecycle hook is set up correctly. Here’s an example of how to do that:

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Step 2: Use Optional Chaining

Instead of hard coding each year, modify your subjectsFilter method to use optional chaining. This way, you can safely access nested properties without running into undefined errors:

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How It Works

Optional Chaining (?.): This operator checks whether the preceding property is defined before attempting to access the next property. If any part of the chain is undefined, it will return undefined instead of throwing an error.

Fallback Value (|| []): If the subject for the specified year and level does not exist, we return an empty array instead of undefined. This helps in ensuring our application remains functional even when the desired data is not present.

Why Is Year Required but Not Level?

You might wonder why you need to define the specific year in your data object but not the level. This typically comes down to how your API structures its data. The years are likely the keys within the subjects object, while the levels could be defined dynamically based on the data returned for each year. Therefore, you can access levels more flexibly without encountering issues seen with changing years.

Conclusion

Avoiding hard coding values in your Vue.js application can save you from running into runtime errors and make your codebase much more flexible and maintainable. By utilizing optional chaining, you can effectively manage your data while allowing your application to adapt to varying data structures from your API responses. This method not only improves your code quality but also enhances user experience.

Implement this change in your code and watch your application handle data more smoothly!