Solving TS2339: Property 'data' does not exist Error in Angular Store Configuration

Описание: Discover how to resolve the TypeScript `TS2339: Property 'data' does not exist` error with proper `props` configuration in Angular's NgRx Store.
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Understanding the TypeScript TS2339 Error in Angular

If you're a developer working with Angular and NgRx, you may have encountered the frustration of type errors while implementing actions and reducers. One such error is TS2339: Property 'data' does not exist. This error can be particularly troublesome when you're striving to maintain strong typing in your application. In this guide, we'll break down the cause of this error and provide a clear solution to ensure your application runs smoothly.

The Problem

The error message usually surfaces when you define your action and reducer with the NgRx store. For example, you might have defined an action to save a user and then subsequently tried to access the data within the reducer. The error occurs due to issues with how TypeScript recognizes the props for your actions.

Error Details

The following TypeScript errors summarize the issues:

For the action:
TS2339: Property 'payload' does not exist on type 'ActionCreatorProps{ payload: User; }'

For the reducer:
TS2339: Property 'data' does not exist on type 'ActionCreatorProps{ data: User; }'

These messages indicate that TypeScript isn't correctly interpreting the shape of your actions. Below, we’ll explore how to resolve these messages step by step.

The Solution

The root cause of these errors is incorrect usage of the props function in your NgRx actions. The props method must be called as a function. Here’s how you can rectify the code in your action.ts and reducer.ts files:

Step 1: Update the Action Definition

In your action.ts, modify the action definitions as follows:

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

Step 2: Adjust the Reducer Implementation

Next, ensure that the reducer accesses the data property correctly. Update your reducer.ts to reflect the changes made in the action definitions:

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

Step 3: Verify Effect Implementation

Finally, in your effect.ts, ensure that the effect remains intact and the save action is exposed correctly:

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

Conclusion

Strong typing in JavaScript can indeed be challenging, but by following these structured steps to revise your action and reducer definitions, you can effectively resolve the TS2339: Property 'data' does not exist error. Remember to always invoke props as a function for your action creators. By implementing these improvements, you can enhance the reliability of your Angular application while adhering to strong typing principles. Happy coding!