CSV to GeoJSON Parser in Web Worker

csv.worker.ts

import { csvParse } from 'd3-dsv';
import { Feature, FeatureCollection, Point } from 'geojson';

function snooze(ms: number): Promise<void> {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

addEventListener('message', async (event: MessageEvent) => {
  const { payload, sleep } = event.data.message;
  await snooze(sleep);
  const data = csvParse(payload);
  const geojson = await transformGeoJSON(data);
  postMessage(geojson);
});

async function transformGeoJSON(payload: any): Promise<FeatureCollection> {
  const geojson: FeatureCollection<Point> = {
    type: 'FeatureCollection',
    features: [],
  } as FeatureCollection<Point>;
  for await (const t of payload) {
    geojson.features.push({
      type: 'Feature',
      properties: {
        userId: t?.userId || null,
        userName: t?.userName || null,
      },
      geometry: {
        type: 'Point',
        coordinates: [
          parseFloat(t?.longitude) || 0,
          parseFloat(t?.latitude) || 0,
        ],
      },
    } as Feature<Point>);
  }
  return geojson;
}