Pipe Angular para Conta Bancária

conta.pipe.ts

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
    name: 'conta'
})
export class ContaPipe implements PipeTransform {
    transform(value: string, args?: any): any {
        if (value) {
            value = value.replace(/\D/g, '');
            value = `${value.substr(0, value.length - 1)}-${value.substr(value.length - 1, 1)}`;
        }
        return value;
    }
}