Angular material mat error

We will make a series of tutorials on Angular material components and in the article, we will explore how to implement Angular material form in the Angular project. Angular Materials provide the developer with reusable UI components that help the developer to use ready-made components, fast development, and one best UI design. In Angular, we can use different UI libraries, but Angular Material is one of the best UI component libraries that are made specifically for Angular.

We have three objectives behind this tutorial, first will learn how to use Angular material form in reactive form and second we’ll look how used different material component like material form field, material hint, error , date picker, material select and material radio buttons. Last how to apply material icon on these material inputs. Let’s get started.

Step 1: Setting up and configuring Angular material form the project

Let’s first create our Angular material form project. In our previous articles, we learned how to install and the best approach for configuring Angular material in our project. Run the following command to create and add Angular Material to our project.

ng new angularMaterialFormApp
cd angularMaterialFormApp
ng add @angular/material

While running the 3rd command will ask you the select theme, material typography, and animation, press yes on all. To use the Angular material component, we have to import it into our app module. Let’s create a module and import all material components on it.

ng g m ng-material

Open src/app/ng-material/ng-material.module.ts and replace the existing code with the code shown below.

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { MatNativeDateModule } from '@angular/material/core';
import { MatDatepickerModule } from '@angular/material/datepicker';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatInputModule } from '@angular/material/input';
import { MatSortModule } from '@angular/material/sort';
import { MatTableModule } from '@angular/material/table';
import { MatIconModule } from '@angular/material/icon';
import { MatSelectModule } from '@angular/material/select';
import { MatRadioModule } from '@angular/material/radio';
import { MatButtonModule } from '@angular/material/button';

@NgModule({
    declarations: [],
    imports: [
        CommonModule,
        MatTableModule,
        MatSortModule,
        MatFormFieldModule,
        MatInputModule,
        MatDatepickerModule,
        MatNativeDateModule,
        MatIconModule,
        MatSelectModule,
        MatRadioModule,
        MatButtonModule,
    ],
    exports: [
        CommonModule,
        MatTableModule,
        MatSortModule,
        MatFormFieldModule,
        MatInputModule,
        MatDatepickerModule,
        MatNativeDateModule,
        MatIconModule,
        MatSelectModule,
        MatRadioModule,
        MatButtonModule
    ]
})
export class NgMaterialModule { }

We are importing all the required modules in our custom material module file and keeping separate modules for Angular material will make the application easy to maintain. Now we need to import our material module and ReactiveFormModule in our src/app/app.module.ts file.

import { NgMaterialModule } from './ng-material/ng-material.module';
@NgModule({
...
imports: [
   ...
  ReactiveFormsModule,
  NgMaterialModule,
],
})

Step 2: Angular material form example

We have completed our configure of material form, now let’s demonstrate the Angular material form example. We have learned that Angular has two different types of forms, template-driven, and reactive forms. We are using the Reactive form to demonstrate the Angular material form example. If you have no idea how to use these forms please check our previous tutorial on them, as in this tutorial we are only focused on how to implement material forms.

Here is a screenshot of our Angular material form example

Step 3: Initialize form and add Angular material form validation rule

In our component typescript, we need to add Angular material form validation rules, like required, email validation, min and max length of the input, etc. Now let’s create a form and add validation in the app.component.ts file

import { Component, OnInit } from '@angular/core';
import { FormGroup, FormBuilder, Validators } from '@angular/forms';

@Component({
  selector: 'app-form',
  templateUrl: './form.component.html',
  styleUrls: ['./form.component.scss']
})
export class FormComponent implements OnInit {
  form: FormGroup = new FormGroup({});

  constructor(private fb: FormBuilder) { }

  ngOnInit(): void {
    this.form = this.fb.group({
      name: [null, [Validators.required, Validators.minLength(10)]],
      email: [null, [Validators.required, Validators.pattern("^[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,4}$")]],
      dob: [null, [Validators.required]],
      address: [null],
      country: [null],
      gender: [null]
    });
  }

  saveDetails(form: any) {
    alert('SUCCESS!! :-)nn' + JSON.stringify(form.value, null, 4));
  }
}

1. required: This attribute is used to specify a value that must be provided.
2. minlength: This attribute is used to specify a minimum number of characters.
3. maxlength: This attribute is used to specify a maximum number of characters. This type of validation cannot be applied directly to form elements because it conflicts with the HTML5 attribute of the same name. It can be used with model-based forms.
4. pattern: This attribute is used to specify a regular expression that the value provided by the user must match.

Here we don’t have to do anything related to material form, as material components are declared and used inside our component template. We have declared form rules and if the form is valid, then we output it through the alert function.

Step 4: Adding material form component in Angular material form template.

Now we will add material form components in our component template, we have used mat-form-field, mat-label, mat-select, mat-radio-button, mat-datepicker-toggle, mat-hint, and mat-error. Here we have listed and uses of material components.

Let’s edit our material form, in the app.component.html file.

<div class="container">
    <form [formGroup]="form" (ngSubmit)="saveDetails(form)">
        <mat-form-field appearance="standard">
            <mat-label>Name</mat-label>
            <input matInput maxlength="15" inputmode="tel" placeholder="Type name" formControlName="name" #nameInput>
            <mat-hint>Mini character 10: {{ nameInput.value.length }}/10</mat-hint>
            <mat-error>Name is required</mat-error>
            <mat-error *ngIf="form.controls['name'].errors?.['minlength']">
                Please enter more than 10 character
            </mat-error>
        </mat-form-field>

        <mat-form-field appearance="legacy">
            <mat-label>Email Address:</mat-label>
            <input matInput type="email" formControlName="email" placeholder="Your email">
            <mat-icon matSuffix>mail_outline</mat-icon>
            <mat-hint>Input the fully qualified email address</mat-hint>
            <mat-error *ngIf="form.controls['email'].errors?.['required']">Email is required</mat-error>
            <mat-error *ngIf="form.controls['email'].errors?.['pattern']">Please enter valid email</mat-error>
        </mat-form-field>

        <mat-form-field appearance="standard">
            <mat-label>Address:</mat-label>
            <textarea matInput placeholder="address" formControlName="address"></textarea>
        </mat-form-field>

        <mat-form-field appearance="fill" hintLabel="Country name required">
            <mat-label>Country</mat-label>
            <mat-select matNativeControl name="country" formControlName="country">
                <mat-option value="india">India</mat-option>
                <mat-option value="france">France</mat-option>
                <mat-option value="germany">Germany</mat-option>
                <mat-option value="japan">Japan</mat-option>
                <mat-option value="Mongolia">Mongolia</mat-option>
            </mat-select>
        </mat-form-field>

        <div style="margin-top:10px;">
            <div style="margin-right:3%; color:#6b6b6b;">
                <mat-label>Gender</mat-label>
            </div>
            <mat-radio-group formControlName="gender">
                <mat-radio-button value="Male">Male</mat-radio-button>
                <mat-radio-button value="Female">Female</mat-radio-button>
            </mat-radio-group>
        </div>

        <mat-form-field class="example-full-width" appearance="fill">
            <mat-label>Choose a date</mat-label>
            <input matInput [matDatepicker]="picker" formControlName="dob">
            <mat-datepicker-toggle matSuffix [for]="picker">
                <mat-icon matDatepickerToggleIcon>keyboard_arrow_down</mat-icon>
            </mat-datepicker-toggle>
            <mat-datepicker #picker></mat-datepicker>
        </mat-form-field>
        <div mat-dialog-actions align="end">
            <button mat-raised-button color="primary" type="submit" [disabled]="!form.valid">Submit</button>
        </div>
    </form>
    <div>{{ form.value | json }}</div>
</div>

The angular material library has a mat-form-field component, which we have used extensively in Material form. This mat-form-field component wraps several material subform components inside it and applies common Text field styles such as the underline, floating label, and hint message on the following form controls.

1. Input text
2. Select text field: mat-select
3. Text area
4. Chip or tags input: mat-chip
5. Date picker

The text input in our component template uses the matInput directive to add material design looks and feel.

How do we validate Angular material form elements?

As we are using a reactive form, we can access each individual form element in our template. Angular form control elements have different states like touched, dirty, errors, valid, invalid, untouched, and pristine. We can access individual elements using the form.get() method with the name of the individual form control element and then we can check its control status.

We have validated, and require minLength and email patterns like this in our template.

<mat-error *ngIf="form.controls['email'].errors?.['required']">
  Email is required
</mat-error>

<mat-error *ngIf="form.controls['email'].errors?.['pattern']">
  Please enter valid email
</mat-error>

<mat-error *ngIf="form.controls['name'].errors?.['minlength']">
  Please enter more than 10 character
</mat-error>

We have learned how to configure and use Angular material form components in angular projects. Let now demonstrate an example of an angular material login form. Here is a screenshot of our angular material login form example.

Let’s edit the app.component.ts file to include the reactive form module, form group, and form builder for the angular material login form.

import { Component, OnInit } from '@angular/core';
import { FormGroup, FormBuilder, Validators } from '@angular/forms';

@Component({
  selector: 'app-form',
  templateUrl: './form.component.html',
  styleUrls: ['./form.component.scss']
})
export class FormComponent implements OnInit {
  form: FormGroup = new FormGroup({});
  flag: boolean = true;

  constructor(private fb: FormBuilder) { }

  ngOnInit(): void {
    this.form = this.fb.group({
      email: [null, [Validators.required, Validators.pattern("^[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,4}$")]],
      password: [null, [Validators.required, Validators.minLength(6)]],
    });
  }

  saveDetails(form: any) {
    alert('SUCCESS!! :-)nn' + JSON.stringify(form.value, null, 4));
  }
}

In our component template, we have used another material component called material card, you need to import MatCardModule in our material module. We also have matSuffix, and matPrefix attributes to set mat-icon at the end or start. As the name suggests that matPrefix adds an icon at the start of input and matSuffix at end of the input.

We have used visibility on and off to see and make password type text visible or password by the toggle flag button. Let’s edit the app.component.html file.

<mat-card>
    <mat-card-title>Login</mat-card-title>
    <mat-card-content>
        <form [formGroup]="form" (ngSubmit)="saveDetails(form)" autocomplete="off">
            <div>
                <mat-form-field appearance="legacy">
                    <mat-label>Email Address:</mat-label>
                    <input matInput type="email" formControlName="email" placeholder="Your email">
                    <mat-icon matSuffix>mail_outline</mat-icon>
                    <mat-hint>Input the fully qualified email address</mat-hint>
                    <mat-error *ngIf="form.controls['email'].errors?.['required']">Email is required</mat-error>
                    <mat-error *ngIf="form.controls['email'].errors?.['pattern']">Please enter valid email</mat-error>
                </mat-form-field>
            </div>

            <div>
                <mat-form-field appearance="standard">
                    <mat-label>Password </mat-label>
                    <input matInput [type]="flag ? 'password' : 'text'" placeholder="Enter your password"
                        formControlName="password">
                    <mat-icon (click)="flag=!flag" matSuffix>{{ flag ? 'visibility' : 'visibility_off' }}</mat-icon>
                    <mat-error>Name is required</mat-error>
                    <mat-error *ngIf="form.controls['password'].errors?.['minlength']">
                        Please enter more than 6 character
                    </mat-error>
                </mat-form-field>
            </div>

            <div>
                <button mat-raised-button color="primary" type="submit" [disabled]="!form.valid">Login</button>
            </div>

        </form>
    </mat-card-content>
</mat-card>

Like before we have added angular material login form validation, when all login inputs are valid, then we will enable the login button.

Angular material input field appearance attribute

Angular material form field component mat-form-field component have appearance attribute, that allows us to apply different appearance on an input field. The mat-form-field have the following four different value we can apply to the appearance attribute.

1. Fill
2. Outline
3. Standard
4. Legacy

How to set autosize to Text area?

We can add the matInput directive on textarea element. The HTML Textarea element has a row attribute to add and configure the numbers of rows on textarea input. But the row attribute is static, we can’t increment or decrement on running the application. The <textarea> elements can be made to automatically resize by using the cdkTextareaAutosize directive available in the CDK.

<mat-form-field appearance="outline">
    <mat-label>Address field: with Appearance attribute outline</mat-label>
    <textarea cdkTextareaAutosize cdkAutosizeMinRows="2"
    cdkAutosizeMaxRows="10" matInput placeholder="address"    
    formControlName="address"></textarea>
 </mat-form-field>

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Conclusion
We have completed our Angular material form tutorial, and we have learned how to use the material form field and Angular material form validation. At last, we have one more example on the Angular material login form to perform password visibility and matPrefix and matSuffix to align icons on input. I hope you had learned something, if so then please share it with others and on social networks, this will encourage me to add more content. Follow me on my GitHub collection, I had code on Angular, react, and Ionic framework.

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