Solving the “Expected 1 arguments, but got 2” Error in TypeScript When Using useState with React

Learn how to effectively resolve the “`Expected 1 arguments, but got 2`” error in TypeScript when working with React's `useState`. This guide walks you through the process step-by-step to ensure smooth functionality in your application.
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Solving the “Expected 1 arguments, but got 2” Error in TypeScript When Using useState with React

In the world of web development, working with React and TypeScript can present unique challenges—one of which is understanding function parameters and interfaces. A common issue you might face is the error message indicating that you are "Expected 1 arguments, but got 2". This can be particularly perplexing when trying to pass a useState setter function to a utility function as you've set up in a React component.

The Problem: Understanding the Error Message

You might find yourself in a situation similar to the following:

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

In this example, fetchUserDoc is designed to accept a single argument that is an object containing the uid and setData. However, when you call it like this:

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

You encounter a TypeScript error stating "Expected 1 arguments, but got 2."

Solution: Restructuring Your Function Call

Step 1: Understanding the Function Signature

The function fetchUserDoc is defined to take a single parameter of type IFetchDocProps:

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

This means that instead of passing two separate arguments, you need to pass a single object that contains both uid and setData.

Step 2: Create an Argument Object

To fix this error, you should create an object that captures both arguments:

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

Step 3: Call Your Function with the Object

Now you can call your function using the object you just created:

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

Example Implementation

Here’s what the corrected implementation might look like:

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

Summary

By understanding that fetchUserDoc expects a single object parameter, you can avoid the confusion caused by the error "Expected 1 arguments, but got 2." The key takeaway here is to structure your function calls based on the expected input, which is particularly crucial in TypeScript where type checks are strictly enforced.

Following these steps will not only solve the immediate issue but will also enhance your understanding of TypeScript interfaces and how they interact with function parameters in React.

Final Note

It's normal to encounter these kinds of errors when working in TypeScript, especially when you're first getting used to its strict typing system. With practice and experience, you'll find it easier to manage your functions and their signatures.

By applying this solution, you can effectively troubleshoot common TypeScript issues, allowing you to focus more on building your application and less on debugging.