Forms are a way to store and update the data of any enterprise web application. The form can provide ease and complexity for the developers to collect and store the data simultaneously.
Angular provides two different approaches through which the developers can build exciting angular reactive forms. The approaches are as follows-
- Template-driven Forms
- Reactive Forms
Template-driven forms use the existing form tag to create the forms. Angular then interprets the form tag and starts a form by getting the representation. The controls are then added using the Ngmodule and can be grouped.
In contrast, the Reactive form is a paradigm. The reactive forms in Angular itself manage the data flow between the control and models. They are code-driven and are easy to use as compared to template-driven forms. It is hence, the most scalable approach to developing dynamic forms.
You can refer to the angular online training course to gain all the necessary information regarding the angular reactive forms.
What are Reactive Forms?
Reactive Forms are a source to manage a specific form state at a particular instant of time. They are a source to ensure the union of your data along with all the changes updated in the source location. It also provides dynamic form validation in which the inputs and values are to be accessed.
Reactive forms can easily be tested as the developer is sure of the data consistency within the form. They provide features such as-
- Safe access to the data model
- Tracking changes through different predictable streams
- Different operators providing immutability of data
In short, the reactive forms in Angular are a way to define the structure of the component class forms. With angular forms, the developers get access to RxJS operators that help them manage and update the state anytime, anywhere, as per their preference.
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Moving ahead in the article, we will now learn the procedure to set up the first reactive forms in Angular. It is a complete process with various steps. One must follow them in their respective order to reduce the probability of getting stuck or facing unwanted errors and warnings. Let's study the process in detail.
When creating the angular reactive forms, we do not use any pre-build modules or the libraries. Instead, we manually create the control setup within the component class.
1. Add Reactive Forms Module
The first step in building up reactive forms in Angular is to add the reactive forms module. You can refer to the below code.
2. Import the Required Modules within the Component
Next, you need to import all the essential modules such as FormArray, FormGroup, FormControl, etc. These classes will add certain functionalities to build up the angular material reactive form.
You can import as many classes as required. We have used three major component classes: FormGroup, FormControl, and FormArray classes.
After importing the classes, your code will look something like this.
3. Use the FormControl Class
The FormControl class is a type of form control used to track the value and validity of the data. It would help if you created a Form control class object whose constructor takes in 3 different parameters, which are-
- An initial data value, which may or may not be null
- Synchronous validators as an array
- Asynchronous validators array.
Note- The last two parameters are optional and unnecessary to run the class. Here's how you create a FormControl class.
The optional parameters are not added in the class constructor as they are not mandatory.
4. Using the FormGroup Class
It is a collection of form controls available in the reactive forms in angular. The various features available in this FormGroup control can be merged into a separate function that provides different API functions.
The FormGroup stores all the properties of its child controls and is the top level of the angular reactive forms. It is more like a single object that combines all the child's controls.
You can refer to the below code to learn how to create a FormGroup.
The above code snippet has two significant controls: email and password.
The complete view of the FormGroup control is shown below.
5. Submit the reactive forms angular
Once the form is created, the last thing is to add a button to submit the angular reactive forms.
- Here is an example code used to set the submit button in a function that will be called as per the requirement.
- A function for submitting a form will be added to the component class. We have a function setup below-
This code has a login user function that will handle all the submit form events. This function lets you read all the values and status of the properties.
6. Add Validations
We need to add the validations to the component class in FormControl.
- You first need to import the validators available in the @angular/form class.
- Now, use the FormGroup class to detect the errors in a specific form control method. We will use this class to identify the validation error in a mail and then display it further.
- If your form is valid, you can add the submit button, and if not, then disable the submit button. This ensures that the users submit no invalid forms.
7. Use ForBuilder Class
It is a class used to shorten your form and make it precise. It simplifies the code for other classes such as FormGroup and FormControl. Simplifying the code is a mandatory step to reduce its length. To use this class, you must refactor the login form.
- First, import the FormBuilder class from the @angular/form class.
- You need to use the same template for both FormBuilder and FormControl classes available. Here's a code snippet for the FormBuilder component.
How to Use Reactive Forms
After creating the angular reactive forms, it's now time to implement and use the reactive forms in Angular. Using the reactive forms angular is not at all a difficult task. It just has a few basic steps to use them properly. The steps are mentioned below.
- Firstly, import the ReactiveFormsModule within their project.
- The next step is to create the form models within the component class. The form model uses different form controls such as FormGroup, FormControl, and FormArrays.
- After importing all the required control classes, you must create an HTML form that follows the basic form model.
- Bind both the HTML form and the form model together.
And, your Angular Material Form Reactive is ready.
Reactive forms in Angular have a practical module called the ng module. This module helps the developers to organize the compilers and the injectors all together in a specific position. It has a class- @NgModule decorator. It has an object describing how to compile the component's template and how to create injectors along with the runtime.
Here's a code for the angular reactive forms example.
Import ReactiveFormsModule
The Reactive form module provides ease to the developers to work with specific HTML pages as per the requirements. It is more like a browser extension that offers different features for the developers while creating the reactive forms angular.
The module can be imported within the component class to use its functionalities.
Here's a code snippet for how to import the ReactiveFormsModule.
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Conclusion
The reactive forms in Angular are a very creative way to quickly gather information from many people. For more details and explanations, you can refer to the KnowledgeHut angular online training guide to get help from our experts to help you develop interactive angular reactive forms.
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