Resolve locations from all checkins from your Foursquare GDPR data export

venues-to-loc.mjs

import { readFile, writeFile } from 'fs/promises';
// Get a Places API key at https://foursquare.com/developers/home.
const FOURSQUARE_PLACES_API_KEY = 'XXX';

// First, collect all deduplicated venue IDs.
let venueIds = new Set();

for (let i = 1; ; i++) {
	try {
		var json = require(`./checkins${i}.json`);
	} catch (e) {
		break;
	}
	for (let item of json.items) {
		try {
			venueIds.add(item.venue.id);
		} catch (e) {
			console.warn('Could not process', item);
			console.warn(e);
		}
	}
}

let venueInfo = Object.create(null);

// Try to load an earlier snapshot in case there was a fatal error.
try {
	venueInfo = JSON.parse(await readFile('venues-data.json', 'utf8'));
} catch {}

try {
	for (let [i, id] of venueIds.entries()) {
    // Ignore already resolved venue IDs from previous snapshot.
		if (id in venueInfo) {
			continue;
		}
		console.log(`Processing venue ${i + 1}/${venueIds.size}`);
    // Resolve GPS coordinates and Foursquare's own geocoding.
		const res = await fetch(`https://api.foursquare.com/v3/places/${id}?fields=geocodes,location`, {
			headers: {
				'Accept': 'application/json',
				'Authorization': FOURSQUARE_PLACES_API_KEY
			}
		});
		let json;
		try {
			if (!res.ok) {
				throw new Error(`HTTP ${res.status}: ${res.statusText}`);
			}
      // Store resolved data.
			json = await res.json();
		} catch (e) {
      // If there's non-recoverable error (e.g. venue is 404 now), just store it as-is, not much we can do.
			json = { error: e.message };
		}
		venueInfo[id] = json;
	}
} finally {
  // If we finished for whatever reason - either success or some fatal error - save the snapshot to a JSON file.
	await writeFile('venues-data.json', JSON.stringify(venueInfo, null, 2));
}