Скачать или смотреть Resolving the AWS Amplify Error: Unrecognized Field in Input Object Type

Learn how to troubleshoot the `AWS Amplify` error regarding undefined field names in input object types, and understand the nuances of GraphQL input and return types.
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This video is based on the question https://stackoverflow.com/q/63428895/ asked by the user 'BigBugCreator' ( https://stackoverflow.com/u/4694090/ ) and on the answer https://stackoverflow.com/a/63470211/ provided by the user 'xadm' ( https://stackoverflow.com/u/6124657/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Handling the AWS Amplify Error: Unrecognized Field in Input Object Type

When working with AWS Amplify and GraphQL, you may occasionally run into issues that can catch you off guard. One such error message that developers might encounter is: "The variables input contains a field name that is not defined for input object type." This error can stem from a misconfiguration in your input fields, especially when you're trying to update specific fields in your schema. In this post, we'll dive deep into the problem and how to effectively resolve it.

Understanding the Problem

Let's break down the core of the issue. You might have a GraphQL schema defined like this:

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

When you attempt to utilize the autogenerated mutation updateMonthResume from Amplify, you may pass an input that looks something like this:

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

However, if your intention is solely to update the incomes, you might call the API with something like this:

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

At this point, you might receive the aforementioned error message. Let's analyze why this is happening.

Why This Error Occurs

The crux of the matter lies within GraphQL's strict input type requirements. Here are a few key points to note:

Defined Properties: The input object can only contain properties that are specifically defined in the UpdateMonthResumeInput type. Think of this as a controlled interface; you can't send more than what's defined, though you can send less if they are nullable or optional.

Required Fields: All required fields must be supplied in your input. If you leave any required field out, GraphQL will throw an error indicating that a field is missing or undefined.

Input vs Return Types: It's vital to understand that there's a difference between input types for mutations and return types for queries and mutations. The error occurs because spendingByCategory isn't part of the UpdateMonthResumeInput unless it's defined explicitly.

Nesting Not Supported: You cannot nest input types for relationships directly in the input object. Just like when creating a user and then associating friends, you can't create a user that immediately has friends in the same mutation call. You have to do it in separate steps or using defined input types.

Steps to Resolve the Error

To fix the error and successfully update your MonthResume, follow these steps:

1. Update Input Structure

You need to ensure that the input structure aligns with what the mutation requires. Modify your update call as follows, including all required fields:

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

2. Separate Mutations for Related Objects

If you need to add categories to spendingByCategory, you'll perform that in a different mutation entirely, as nested mutations aren't supported in this structure.

3. Consult the GraphQL Schema

Always refer back to your GraphQL schema for what fields are defined and required. If you're unsure how to structure your inputs, the schema will provide clarity.

Conclusion

Working with AWS Amplify and GraphQL offers significant power in building applications, but leveraging these tools comes with their own set of challenges. By understanding the nuances of GraphQL input types and ensuring that your inputs match what is defined in your operations, you can avoid pitfalls such as the one we've discussed here.

By taking the time to resolve these input issues, you can ensure your applications run smoothly and benefit from the dynamic capabilities that AWS Amplify provides. Happy coding!