Angular 5 - Only Number Input, Only Number Decimal

only-number.directive.md

Angular 5,6,7,8,9 - Only Number Input, Only Decimal Input

Online Demo: https://codesandbox.io/s/purple-monad-ljwlb?fontsize=14&hidenavigation=1&module=%2Fsrc%2Fapp%2Fnumeric.directive.ts&theme=dark

Allow Only Numbers (Without Decimal)

<input numeric type="text">

Allow Numbers & Only Two Decimals [0-9] (With Decimal Limit)

<input numeric decimals="2" type="text">

import {Directive, ElementRef, HostListener, Input} from '@angular/core';

@Directive({
    selector: '[numeric]'
})

export class NumericDirective {

    @Input('decimals') decimals: int = 0;

    private check(value: string, decimals: int)
    {
      if (decimals <= 0) {
        return String(value).match(new RegExp(/^\d+$/));
      } else {
          var regExpString = "^\\s*((\\d+(\\.\\d{0," + decimals + "})?)|((\\d*(\\.\\d{1," + decimals + "}))))\\s*$"
          return String(value).match(new RegExp(regExpString));
      }
    }

    private specialKeys = [ 
      'Backspace', 'Tab', 'End', 'Home', 'ArrowLeft', 'ArrowRight', 'Delete'
    ];

    constructor(private el: ElementRef) {
    }

    @HostListener('keydown', [ '$event' ])
    onKeyDown(event: KeyboardEvent) {
        if (this.specialKeys.indexOf(event.key) !== -1) {
            return;
        }
        // Do not use event.keycode this is deprecated.
        // See: https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode
        let current: string = this.el.nativeElement.value;
        let next: string = current.concat(event.key);
        if ( next && !this.check(next, this.decimals) ) {
           event.preventDefault();
        }
    }
}

Thanks.

I also added the following changes so I can edit the number at any place in the input:

let current: string = this.el.nativeElement.value;
let position: number = this.el.nativeElement.selectionStart;
let next: string = [current.slice(0, position), event.key, current.slice(position)].join('');

I would also suggest to check condition on Backspace and Delete.

it's not working fine when i am entering text this field accepting text

It's work fine.

I have a question, if I need put a variable inside, how could I do?

I try

x:number = 0;
 y:number = 2;

private regex = {
        number: new RegExp(/^\d+$/),
        decimal : new RegExp("^\\d{"+ x +","+ y +"}$", "g")
    };

also
decimal: new RegExp(/^\d*\,?\d{"+ x +","+ y +"}$/g)

but didn't work

Any suggestion? Because I need use that like a parameter (the user put how many decimal want to use)

@darwinguz Thank you. Added "Delete" key.

@Jozx thank you for your message. I updated the directive and added a decimal limit option.

The directive is much cleaner than before :)

@ahmeti How to make this directive work for negative values

@ahmeti Thank you so much. It's perfectly worked.

when it is putting application level it is not working in individual module it is working file , so how to application levelel ? i.e. if we put in app.module.ts file importing file and declaration of file not working..

@ahmeti how to allow copy & paste with this?

I am using the directive with two decimal places. If the existing value has two decimals (1.23), the directive does not let me type anything else, even if the cursor is in front of the decimal point. Is there a way to get around that?

Thank you guys. I updated and please check to a new version. @isoftvn @rob-byram

@ahmeti, thank you so much!! I spent a good portion of today trying (unsuccessfully) to do a workaround that also dealt with the "selected" characters. Your update is super simple and works like a charm!

@ahmeti, Hey thanks so much! It has been quite useful!

@ahmeti How can I change the RegExp to accept negative numbers? Equal that now, but accpeting one or none "-" at first.

Thanks so much.

@ahmeti How to make this directive work for negative values

+1

Now supports negative values.
But i don't want to change base directive.
I added negative prop in component. If you want you can use the directive bellow.

@albertThinkpalm @carlosesteban55

<input numeric type="text" negative="1" />

import { Directive, ElementRef, HostListener, Input } from "@angular/core";

@Directive({
  selector: "[numeric]"
})
export class NumericDirective {
  @Input("decimals") decimals: int = 0;
  @Input("negative") negative: int = 0;

  private checkAllowNegative(value: string) {
    if (this.decimals <= 0) {
      return String(value).match(new RegExp(/^-?\d+$/));
    } else {
      var regExpString =
        "^-?\\s*((\\d+(\\.\\d{0," +
        this.decimals +
        "})?)|((\\d*(\\.\\d{1," +
        this.decimals +
        "}))))\\s*$";
      return String(value).match(new RegExp(regExpString));
    }
  }

  private check(value: string) {
    if (this.decimals <= 0) {
      return String(value).match(new RegExp(/^\d+$/));
    } else {
      var regExpString =
        "^\\s*((\\d+(\\.\\d{0," +
        this.decimals +
        "})?)|((\\d*(\\.\\d{1," +
        this.decimals +
        "}))))\\s*$";
      return String(value).match(new RegExp(regExpString));
    }
  }

  private run(oldValue) {
    setTimeout(() => {
      let currentValue: string = this.el.nativeElement.value;
      let allowNegative = this.negative > 0 ? true : false;

      if (allowNegative) {
        if (
          !["", "-"].includes(currentValue) &&
          !this.checkAllowNegative(currentValue)
        ) {
          this.el.nativeElement.value = oldValue;
        }
      } else {
        if (currentValue !== "" && !this.check(currentValue)) {
          this.el.nativeElement.value = oldValue;
        }
      }
    });
  }

  constructor(private el: ElementRef) {}

  @HostListener("keydown", ["$event"])
  onKeyDown(event: KeyboardEvent) {
    this.run(this.el.nativeElement.value);
  }

  @HostListener("paste", ["$event"])
  onPaste(event: ClipboardEvent) {
    this.run(this.el.nativeElement.value);
  }
}

Thanks a lot @ahmeti!!

Now supports negative values and separator="," default "."

<input numeric type="text" decimals="2" negative="1" separator=","/>

import { Directive, ElementRef, HostListener, Input } from "@angular/core";

@Directive({
  selector: "[numeric]"
})
export class NumericDirective {
  @Input("decimals") decimals: number = 0;
  @Input("negative") negative: number = 0;
  @Input("separator") separator: string = ".";

  private checkAllowNegative(value: string) {
    if (this.decimals <= 0) {
      return String(value).match(new RegExp(/^-?\d+$/));
    } else {
      var regExpString =
        "^-?\\s*((\\d+(\\"+ this.separator +"\\d{0," +
        this.decimals +
        "})?)|((\\d*(\\"+ this.separator +"\\d{1," +
        this.decimals +
        "}))))\\s*$";
      return String(value).match(new RegExp(regExpString));
    }
  }

  private check(value: string) {
    if (this.decimals <= 0) {
      return String(value).match(new RegExp(/^\d+$/));
    } else {
      var regExpString =
        "^\\s*((\\d+(\\"+ this.separator +"\\d{0," +
        this.decimals +
        "})?)|((\\d*(\\"+ this.separator +"\\d{1," +
        this.decimals +
        "}))))\\s*$";
      return String(value).match(new RegExp(regExpString));
    }
  }

  private run(oldValue) {
    setTimeout(() => {
      let currentValue: string = this.el.nativeElement.value;
      let allowNegative = this.negative > 0 ? true : false;

      if (allowNegative) {
        if (
          !["", "-"].includes(currentValue) &&
          !this.checkAllowNegative(currentValue)
        ) {
          this.el.nativeElement.value = oldValue;
        }
      } else {
        if (currentValue !== "" && !this.check(currentValue)) {
          this.el.nativeElement.value = oldValue;
        }
      }
    });
  }

  constructor(private el: ElementRef) {}

  @HostListener("keydown", ["$event"])
  onKeyDown(event: KeyboardEvent) {
    this.run(this.el.nativeElement.value);
  }

  @HostListener("paste", ["$event"])
  onPaste(event: ClipboardEvent) {
    this.run(this.el.nativeElement.value);
  }
}

Thanks a lot @ahmeti!!

thanks works as Expected, but only thing is if i use [(ngmodel)] the textbox value is not matched with ngmodel

@ahmeti It's working fine on Chrome but in Firefox and Internet explorer its not working. Can you please suggest?

it is not working in mobile device

thanks works as Expected, but only thing is if i use [(ngmodel)] the textbox value is not matched with ngmodel

Same issue

thanks works as Expected, but only thing is if i use [(ngmodel)] the textbox value is not matched with ngmodel

Same issue

please set value to ngControl

private run(oldValue) {
setTimeout(() => {
let currentValue: string = this.el.nativeElement.value;
let allowNegative = this.negative > 0;
if (allowNegative) {
if (!['', '-'].includes(currentValue) && !this.checkAllowNegative(currentValue)) {
this.ngControl.control.setValue(oldValue, {emitEvent: false})
}
} else {
if (currentValue !== '' && !this.check(currentValue)) {
this.ngControl.control.setValue(oldValue, {emitEvent: false})
}
}
});
}

I want to add prevent default function when user try to enter alphabetical values and other things is that when I try to add numbers at max typing speed it accept more then given decimal values.
For example Input accept 2 decimal values but when try to forcefully enter the values it accepts more then 2 decimals. Any solution will help me to prevent this thing.
Thanks in advance.

How are you removing the zeros in the front (00012)?

To access ngControl, add @Optional() @Self() private ngControl: NgControl, to constructor:

 constructor(
    @Optional() @Self() private ngControl: NgControl,
    private el: ElementRef<HTMLInputElement | HTMLTextAreaElement>,
  ) { }

    if (this.ngControl) {
      this.ngControl.control.patchValue(oldValue, { emitEvent: false, onlySelf: true });
    }

Thank you, very useful!
As @rbrijesh mentioned, if one types more than the maximum decimals, the input does not show it, but the value of the input is longer by one number. Is there a fix for this? I could not find what causes it.

Here is a fixed version. It uses NgControl.valueChanges insted of @HostListeners which fixes the extra character at the end of the input when submitting the form.

`

import { Directive, Input, OnInit } from '@angular/core';
import { NgControl } from '@angular/forms';
import { distinctUntilChanged, pairwise, Subscription } from 'rxjs';

@Directive({
    selector: '[restrictedDecimals]'
})
export class InstrumentDecimalsDirective implements OnInit {
    @Input() decimals = 0;
    @Input() negative = 0;
    @Input() separator = ',';
    valueSubscription: Subscription;

    constructor(public ngControl: NgControl) {}

    ngOnInit(): void {
        this.ngControl.valueChanges.pipe(distinctUntilChanged(), pairwise()).subscribe(([oldValue, newValue]) => {
            this.runCheck(oldValue, newValue);
        });
    }

    private runCheck(oldValue, newValue) {
        const allowNegative = this.negative > 0 ? true : false;

        if (allowNegative) {
            if (!['', '-'].includes(newValue) && !this.checkAllowNegative(newValue)) {
                this.ngControl.control.setValue(oldValue);
            }
        } else {
            if (newValue !== '' && !this.check(newValue)) {
                this.ngControl.control.setValue(oldValue);
            }
        }
    }

    private checkAllowNegative(value: string) {
        if (this.decimals <= 0) {
            return new RegExp(/^-?\d+$/).exec(String(value));
        } else {
            const regExpString =
                '^-?\\s*((\\d+(\\' + this.separator + '\\d{0,' + this.decimals + '})?)|((\\d*(\\' + this.separator + '\\d{1,' + this.decimals + '}))))\\s*$';
            return new RegExp(regExpString).exec(String(value));
        }
    }

    private check(value: string) {
        if (this.decimals <= 0) {
            return new RegExp(/^\d+$/).exec(String(value));
        } else {
            const regExpString =
                '^\\s*((\\d+(\\' + this.separator + '\\d{0,' + this.decimals + '})?)|((\\d*(\\' + this.separator + '\\d{1,' + this.decimals + '}))))\\s*$';
            return new RegExp(regExpString).exec(String(value));
        }
    }
}

`

is there any new update for 13

is there any new update for 13

it works with angular v14