Class for calculate digit verification of the NIT in Colombia in TypeScript

calculateDigitVerification.ts

export class NitValidations {
  static returnVerificationDigit(myNit: string) {
    // Se limpia el Nit
    let validNit = this.cleanNit(myNit);
    // Si el Nit es válido, devuelve el digito
    if (validNit) {
      return this.calculateVerificationDigit(validNit);
    }
  }

  static calculateVerificationDigit(nit: string) {
    let vpri = new Array(16);
    let totalSum: number = 0;
    let cedulaDigit: number = 0;
    let result: number = null;

    vpri = [null, 3, 7, 13, 17, 19, 23, 29, 37, 41, 43, 47, 53, 59, 67, 71];

    for (var i = 0; i < nit.length; i++) {
      cedulaDigit = Number(nit.substr(i, 1));
      totalSum += cedulaDigit * vpri[nit.length - i];
    }
    result = totalSum % 11;

    return result > 1 ? 11 - result : result;
  }

  static cleanNit(nit: any) {
    nit = nit.replace(/\s/g, ''); // spaces
    nit = nit.replace(/,/g, ''); // commas
    nit = nit.replace(/\./g, ''); // dots
    nit = nit.replace(/-/g, ''); // dashes

    if (isNaN(nit)) {
      return null;
    }
    return nit;
  }
}