Angular FormControl ZipCode Directive for North America

zip-code.directive.ts

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

/*
 * Directive to format zip codes on FormControl
 */

@Directive({
    selector: '[zipCode]'
})
export class ZipCodeDirective {
    @Input('country') 
    public country: CountryEnum = CountryEnum.USA;
    protected hyphenKeyCode: number = 189;
    protected backSpaceKeyCode: number = 8;
    constructor(protected el: ElementRef, protected ngControl: NgControl) { }

    @HostListener('keyup', ['$event'])
    protected onkeyup(event): void {
        const keyCode: number = event.keyCode;
        let value: string = this.ngControl.control.value;
        if (!value || value.length === 0 || keyCode === this.backSpaceKeyCode) return;
        value.toString().trim();
        switch (this.country) {
            case CountryEnum.USA:
                if (!(keyCode === this.hyphenKeyCode && value.length === 6))
                    value = value.replace(/[^0-9]/g, '');
                if (value.length > 9)
                    value = value.slice(0, 9);
                if (value.length > 5 && value[5] !== '-')
                    value = value.slice(0, 5) + "-" + value.slice(5);
                break;
            case CountryEnum.CAN:
                value = value.toUpperCase();
                break;
        }
        this.el.nativeElement.value = value;
        this.ngControl.control.setValue(value);
    }
}