Скачать или смотреть Understanding Vue 3 Form Validation: Fixing Common Errors in Your CRUD App

Learn how to resolve a common form validation issue in your Vue 3 application by understanding how to properly call your validation functions.
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Understanding Vue 3 Form Validation: Fixing Common Errors in Your CRUD App

Working with forms in Vue 3 can sometimes lead to confusing moments, particularly when it comes to validating user inputs. Recently, a developer encountered a challenging validation problem in their "Add New User" functionality within a CRUD application. They were trying to ensure that no field in the form was left empty, but the validation results weren't reflecting what they expected. Let’s take a closer look at the problem and how to solve it step by step.

The Problem: Incorrect Validation Output

The developer's goal was to ensure that when the "Add New User" form was submitted, it would validate some basic criteria:

First name should not be empty

Last name should not be empty

Email should not only be present but valid

However, after running the validation script, the developer noticed that the formErrors array did not contain an error for empty fields as intended. Instead, it only stated:

"The email is invalid"

This led to confusion as the expected output should have included messages for empty fields, resulting in:

"There are empty fields"

"The email is invalid"

Key Insight

The main issue was due to the way the validation function isNotEmpty was being called (or not called). This oversight is a common pitfall in JavaScript programming and particularly in Vue that can easily be fixed.

The Solution: Properly Calling Functions

To resolve this issue, the developer needed to adjust the way they checked for non-empty fields. Let’s break down the steps to fix the validation function.

Step 1: Understanding the Function Call

In the original code, the developer had the condition as follows:

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

Here, this.isNotEmpty is referencing the function itself but not executing it. Therefore, the check was incorrectly assessing whether isNotEmpty was defined rather than its logical output (true or false).

Step 2: Correcting the Function Invocation

To properly check if the form fields are indeed validated as non-empty, they must invoke the function using parentheses ():

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

By adding the parentheses, you are effectively calling the function and accessing its return value, which is what is needed for the condition to operate correctly.

Final Code Implementation

The complete conditional check should look something like this within your Vue component:

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

Conclusion: Validation Made Easy

Proper function invocation is a critical part of working with Vue and JavaScript. By ensuring that methods are called correctly, developers can easily validate user inputs and ensure a smooth user experience. The next time you're tackling form validations in your Vue 3 application, remember to check if you are calling those functions correctly!

Happy coding, and may your form validations always be error-free!