10 Angular Reactive Form Best Practices

Angular Reactive Forms are a powerful way to build forms in Angular. They provide a simple and straightforward way to create forms with a wide range of features. However, there are some best practices that should be followed when using Angular Reactive Forms.

In this article, we will discuss 10 best practices for using Angular Reactive Forms. We will cover topics such as form validation, form structure, and form performance. Following these best practices will help you create better forms and improve the user experience.

1. Use the FormBuilder to create your form model

The FormBuilder is a powerful tool that allows you to quickly and easily create complex forms with minimal code. It also provides an easy way to access the form’s values, which makes it easier to debug and maintain your code. Additionally, using the FormBuilder helps keep your code DRY (Don’t Repeat Yourself) by avoiding unnecessary duplication of code.

Using the FormBuilder can help make your Angular reactive forms more efficient and easier to manage.

2. Always use a custom validator function for validation logic

Using a custom validator function allows you to have more control over the validation logic. You can easily add or remove validation rules, and you can also customize the error messages that are displayed when an input fails validation. This makes it easier for users to understand why their input is invalid and how they can fix it.

Additionally, using a custom validator function helps keep your code DRY (Don’t Repeat Yourself). Instead of writing out the same validation logic multiple times in different places, you can just write it once and use it everywhere. This will save time and make your code much cleaner and easier to maintain.

3. Avoid subscribing in templates, instead use async pipe

Subscribing in templates can lead to memory leaks, as the subscription will remain active even after the component is destroyed. This can cause performance issues and unexpected behavior.

The async pipe on the other hand automatically unsubscribes when the component is destroyed, so it’s a much better practice to use this instead of subscribing in the template. It also makes your code more readable and easier to maintain.

4. Use getters to access controls and groups

Using getters to access controls and groups makes it easier to read the code, as you don’t have to keep track of all the different form control names. It also helps with refactoring, since if you need to change a control name, you only need to update the getter instead of searching through your entire codebase for references to that control. Finally, using getters can help reduce errors, since they provide type safety when accessing form controls.

5. Use setValue() or patchValue() over direct control manipulation

When you use setValue() or patchValue(), the form control’s value is updated and the validation state is reset. This ensures that any validations associated with the form control are triggered, which helps to ensure data integrity.

On the other hand, when you manipulate a form control directly (e.g., setting its value property), the form control’s value is updated but the validation state is not reset. This means that any validations associated with the form control will not be triggered, which can lead to invalid data being submitted.

6. Prefer using updateOn: ‘blur’ on input fields

When using updateOn: ‘blur’, the form will only be updated when the user leaves the input field. This prevents unnecessary updates to the form, which can cause performance issues if there are a lot of fields in the form. It also helps reduce the amount of validation errors that appear on the screen at once, as the form won’t be validated until the user has finished entering their data.

Using updateOn: ‘blur’ is especially useful for forms with complex validations or large amounts of data, as it reduces the number of times the form needs to be re-validated and improves the overall user experience.

7. Use ng-container to group elements without adding extra nodes to DOM

When you use ng-container, it allows you to group elements without adding extra nodes to the DOM. This helps keep your HTML clean and organized, which makes it easier for developers to read and understand. It also reduces the amount of code needed to create a form, making it more efficient. Additionally, using ng-container can help improve performance since there are fewer nodes in the DOM.

8. Use CSS flexbox layout to align form controls

Flexbox is a powerful layout system that makes it easy to align elements in both the horizontal and vertical directions. It also allows you to easily adjust the size of elements, which can be useful when creating forms with multiple input fields. Additionally, flexbox provides an intuitive way to create responsive designs, so your form will look great on any device.

Using flexbox for Angular reactive forms helps ensure that all of your form controls are properly aligned and sized, making them easier to read and use. This ultimately leads to better user experience and higher conversion rates.

9. Use reactive forms directives with template driven forms

Reactive forms directives are more powerful and flexible than template driven forms. They allow you to create complex form structures with minimal code, while still providing the same level of validation as a template driven form. Additionally, reactive forms provide better performance since they don’t require the entire form to be re-rendered when changes occur.

Using reactive forms directives with template driven forms also allows for easier maintenance and debugging. Since both types of forms use the same syntax, it’s easy to switch between them without having to learn new concepts or rewrite existing code. This makes it much simpler to debug any issues that may arise.

10. Use the resetForm() method when you want to clear the entire form

The resetForm() method will clear all of the form controls and set them back to their initial values. This is useful when you want to start fresh with a new form, or if you need to reset the form after an unsuccessful submission attempt. It’s also helpful for debugging purposes, as it allows you to quickly reset the form without having to manually change each control value.