Accessing props Object Properties in Vue 3 with TypeScript

Learn how to properly access `props` object properties in Vue 3 using TypeScript and fix common type errors efficiently.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Access props object properties Vue 3 + TS

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Accessing Props Object Properties in Vue 3 with TypeScript

When working with Vue 3 and TypeScript, developers often encounter difficulties accessing properties of props objects passed from parent components to child components. This problem can lead to frustrating error messages, particularly when the TypeScript compiler expresses uncertainty about the structure of objects. One common error message is: "Property 'found' does not exist on type 'Object'." In this guide, we will break down the solution to this issue, ensuring that you can access the properties of your props efficiently and without errors.

The Problem

In a Vue 3 application, you might find yourself needing to access specific properties of an object defined in your parent component. Let's take a closer look at a simple example:

Parent Component

Here's a snippet from our parent component, which contains an object called lettersState:

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

In this code, the lettersState object contains three properties: found, miss, and hint. We are passing lettersState to a child component called Keyboard:

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

Child Component

In the child component, we attempt to access the found property with the following code:

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

The Issue

The Solution

To resolve this issue, it is crucial to define the type of our lettersState object in a way that TypeScript can understand its structure. Instead of merely declaring it as an Object, we need to create a specific type that reflects its properties accurately.

Step 1: Define the Type

We can define a custom type called LetterState that corresponds to the structure of lettersState. This type will inform TypeScript what properties are present in the object:

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

Step 2: Update the Props Definition

Next, we need to update our props definition in the child component. Rather than using the generic Object type, we will reference our newly created LetterState type:

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

With this change, TypeScript now knows that lettersState contains the properties found, miss, and hint, which can be accessed without errors.

Step 3: Access the Property

Finally, we can safely access the found property within our child component without encountering any type errors:

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

Conclusion

By specifying the structure of your props with detailed type definitions, you can avoid type errors that arise from generic object declarations in TypeScript. This practice not only enhances the quality of your code but also improves maintainability and readability.

Make sure to apply the lessons from this post whenever you are working with props in Vue 3 with TypeScript. Understanding and defining your data types will go a long way in creating clean and efficient applications.

Now you’re all set to leverage the power of TypeScript with Vue 3. Happy coding!