Скачать или смотреть How to Set Up Vue 3 Composition API with TypeScript to Push User-Inputted Values to an Array

Learn how to configure the Vue 3 Composition API with TypeScript to effectively manage user input in a todo list app, avoiding common type errors.
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This video is based on the question https://stackoverflow.com/q/70728551/ asked by the user 'JS_is_awesome18' ( https://stackoverflow.com/u/9388426/ ) and on the answer https://stackoverflow.com/a/70728585/ provided by the user 'Owl' ( https://stackoverflow.com/u/12397250/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Mastering Vue 3 Composition API with TypeScript: Handling User Input in a ToDo List App

Building a todo list app is a great way to get started with Vue 3's Composition API, especially when using TypeScript. However, if you're new to these technologies, you may encounter some challenges along the way. One common issue involves type errors when trying to push user-inputted values into an array. In this post, we will explore how to tackle this problem, allowing you to enhance your app with user input seamlessly.

The Problem: Type Error with User Inputs

While working on your todo list app, you attempt to implement a submit function that adds user-inputted values to an array. However, you might run into an error like:

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This error occurs in TypeScript because it doesn't know the type of the array you are trying to push the input into. Let's look at the relevant code snippet that causes the issue:

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Since you're using the ref method from Vue and haven’t specified the type for listItems, TypeScript defaults the type to never, leading to the error when you try to push a string into the array.

The Solution: Declaring the Type for listItems

To resolve this issue, it's crucial to declare the typing for listItems correctly. Here’s how you can do that:

Step 1: Update the Declaration

Modify your listItems declaration to specify that it's an array of strings:

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

By declaring it like this, you inform TypeScript that listItems is an array that will store values of type string. This change allows TypeScript to understand what kind of data it should expect, thus eliminating the error.

Step 2: Complete Code Example

Here’s the complete revised code for your todo list app component:

Template

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Script

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Conclusion

By declaring array types appropriately in TypeScript, you can effectively manage user input and avoid common pitfalls. With this solution, your todo list app will function smoothly, allowing you to push user-inputted values into your listItems array without any type errors.

Final Thoughts

Building applications with Vue 3 and TypeScript can be incredibly rewarding. Remember, thorough type declarations help you write more robust and error-free code. Happy coding!