@opengis/fastify-table/dist/server/plugins/util/funcs/eventStream.js

core-plugins

/* eslint-disable no-console */
/* eslint-disable no-param-reassign */
export default function eventStream(res) {
    if (!res)
        return console.log;
    const time = Date.now();
    // eslint-disable-next-line no-underscore-dangle
    if (!res?._headerSent && !res.sent) {
        res.raw.writeHead(200, {
            'Content-Type': 'text/event-stream; charset=utf-8',
            'Cache-Control': 'no-cache',
            Connection: 'keep-alive',
            'X-Accel-Buffering': 'no',
        });
        res.hijack();
    }
    let prev = time;
    function send(mes, finish) {
        const t1 = Date.now();
        res.raw.write(`data: ${finish ? 'finish' : ''} ${typeof mes === 'object' ? JSON.stringify(mes) : mes} ${t1 - prev}/${t1 - time}ms\n\n`);
        prev = t1;
        if (finish) {
            res.raw.write('data: finish');
            res.raw.end('');
        }
    }
    return send;
}