How to restrict special characters in input field in angular

How to restrict special characters in input field in Angular:

In Angular, you can restrict special characters in an input field by using built-in directives or custom validators.

Method 1: Using built-in directives

1. First, import the necessary modules in your Angular component:

import { FormsModule, ReactiveFormsModule } from '@angular/forms';
    

2. Add the required modules to the imports array of your Angular module:

@NgModule({
  imports: [
    FormsModule,
    ReactiveFormsModule
  ],
  // Other declarations, providers, etc.
})
export class AppModule { }
    

3. In your component’s template, use the pattern attribute with a regular expression to allow only certain characters:

<input type="text" name="myInput" pattern="[a-zA-Z0-9]+" [(ngModel)]="myVariable" required>
    

Method 2: Using custom validators

1. First, create a custom validator function in your Angular component:

import { AbstractControl, ValidatorFn } from '@angular/forms';

export function specialCharacterValidator(): ValidatorFn {
  return (control: AbstractControl): {[key: string]: any} | null => {
    const regex = /^[a-zA-Z0-9]+$/; // Regular expression for allowing only alphanumeric characters
    const isValid = regex.test(control.value);

    return isValid ? null : {'specialCharacters': {value: control.value}};
  };
}
    

2. Add the custom validator to your input field:

<input type="text" name="myInput" [ngModel]="myVariable" [validators]="specialCharacterValidator()" required>
    

Example:

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

@Component({
  selector: 'app-my-component',
  template: `
    <form [formGroup]="myForm">
      <input type="text" formControlName="myInput" required>
    </form>
  `,
})
export class MyComponent {
  myForm: FormGroup;

  constructor() {
    this.myForm = new FormGroup({
      myInput: new FormControl('', [Validators.required, specialCharacterValidator()]),
    });
  }
}