[bug] File not rotating when using a generator function

[JosuerBague]

Hey there, I'm trying to use you package for my pino logger like so:

import { Logger as PinoLogger } from './logger.package';
const rfsa = require('rotating-file-stream');

const pad = (num: number) => (num > 9 ? ""  : "0") + num;

const generator = () => {
    const time = new Date();

    const year = time.getFullYear();
    const month = pad(time.getMonth() + 1);
    const day = pad(time.getDate());
    const hour = pad(time.getHours());

    return `application-${year}-${month}-${day}-${hour}.log`;
}

const stream = rfsa.createStream(generator, {
    interval: '15s',
    compress: true,
    path: 'logs'
})

const logger = new PinoLogger(stream);

export { logger };
export type { ILogger } from './libs/interfaces/interfaces';

This doesn't rotate the file. But when I provide a filename directly like so, it does:

const stream = rfsa.createStrearm('sample.log', { interval: '15s', compress: true, path: 'logs' })