Generate validator message

validator.component.ts

/**
   * Check if the validator has a custom validation message
   *
   * @param errors
   *
   * @return string
   */
  public message(errors: ValidationErrors | null): string {
    const properties = Object.keys(errors);
    let customMessage: boolean;

    if (this.customValidation) {
      customMessage = (properties.indexOf(this.customValidation.name) > -1);
    }

    return customMessage ? this.customValidation.text : `validators.${properties[0]}`;
  }