Securing user input in Angular: A guide to preventing unauthorized text entry

Question

Securing user input in Angular: A guide to preventing unauthorized text entry

I am looking for a way to stop users from inputting multiple spaces. I have tried various solutions like the one provided in this link:

Unfortunately, none of them have worked for my specific case.

Although the code below works well generally, it doesn't solve my issue:

import { AbstractControl } from '@angular/forms';
export function removeSpaces(control: AbstractControl) {
  if (control && control.value && !control.value.replace(/\s/g, '').length) {
    control.setValue('');
  }
  return null;
}

I need a solution that will prevent users from entering repeated spaces, such as typing "John ________ John-TEST ________ TEst".

The underscores represent multiple spaces on the keyboard.

If you know of a directive or have a solution, please share it with me.

angular typescript

Answer 1

Answer №1

To detect when the space key is pressed and prevent the event if the last character in an input text-value is a space, you can create a directive using @HostListener along with either ElementRef or Input.

@HostListener('keydown.space', ['$event']) handler(event: KeyboardEvent) {
    console.log(event);
    if (this.input.endsWith(' ')) {
       event.preventDefault();
    }
}

Alternatively, you can omit .space from the event listener and instead check if the character in the event is a space before handling it.

Answer 2

To detect when the space key is pressed and prevent the event if the last character in an input text-value is a space, you can create a directive using @HostListener along with either ElementRef or Input.

@HostListener('keydown.space', ['$event']) handler(event: KeyboardEvent) {
    console.log(event);
    if (this.input.endsWith(' ')) {
       event.preventDefault();
    }
}

Alternatively, you can omit .space from the event listener and instead check if the character in the event is a space before handling it.

Answer 3

Answer №2

If you want to achieve the outcome you desire, consider utilizing the power of rxjs operators such as debounceTime and distinctUntilChanged:

 this.searchField.valueChanges
  .pipe(debounceTime(800), distinctUntilChanged())
  .subscribe((result) => console.log(result));
}

Answer 4

If you want to achieve the outcome you desire, consider utilizing the power of rxjs operators such as debounceTime and distinctUntilChanged:

 this.searchField.valueChanges
  .pipe(debounceTime(800), distinctUntilChanged())
  .subscribe((result) => console.log(result));
}

Answer 5

Answer №3

To achieve this functionality, you can use a combination of basic HTML and JavaScript or choose to implement it using JS logic.

Here is an example of HTML code for an input element:

If you want to notify the user when they enter multiple spaces:

<input oninput="javascript: if (this.value.match(/  +/g)) window.alert('Multiple Spaces Entered');">

This code snippet will reduce multiple consecutive spaces to just one space immediately:

<input oninput="javascript: if (this.value.match(/  +/g)) this.value = this.value.replace(/  +/g, ' ');">

Answer 6

To achieve this functionality, you can use a combination of basic HTML and JavaScript or choose to implement it using JS logic.

Here is an example of HTML code for an input element:

If you want to notify the user when they enter multiple spaces:

<input oninput="javascript: if (this.value.match(/  +/g)) window.alert('Multiple Spaces Entered');">

This code snippet will reduce multiple consecutive spaces to just one space immediately:

<input oninput="javascript: if (this.value.match(/  +/g)) this.value = this.value.replace(/  +/g, ' ');">

Answer 7

Answer №4

Check out this code snippet for reducing multiple spaces to a single space.

 ngOnInit(): void {
    this.control.valueChanges.subscribe((str: string) => {
      const newVal = str.replace( /  +/g, ' ' )
      this.control.setValue(newVal, {emitEvent: false});
 })

You could also opt for a without-space directive:

export class WithoutSpacesDirective {
  @HostListener('input', ['$event'])
  onKeyDown(event: KeyboardEvent) {
    const input = event.target as HTMLInputElement;
    const newVal = input.value.replace( /  +/g, ' ' )
    
    input.value = newVal; 
  }
}

Here's how it can be used in HTML:

<input type="text" without-spaces [formControl]="control" />

Visit the StackBlitz link for live demo and implementation details.

Answer 8

Check out this code snippet for reducing multiple spaces to a single space.

 ngOnInit(): void {
    this.control.valueChanges.subscribe((str: string) => {
      const newVal = str.replace( /  +/g, ' ' )
      this.control.setValue(newVal, {emitEvent: false});
 })

You could also opt for a without-space directive:

export class WithoutSpacesDirective {
  @HostListener('input', ['$event'])
  onKeyDown(event: KeyboardEvent) {
    const input = event.target as HTMLInputElement;
    const newVal = input.value.replace( /  +/g, ' ' )
    
    input.value = newVal; 
  }
}

Here's how it can be used in HTML:

<input type="text" without-spaces [formControl]="control" />

Visit the StackBlitz link for live demo and implementation details.

Securing user input in Angular: A guide to preventing unauthorized text entry

Answer №1

Answer №2

Answer №3

Answer №4

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