Generate IANA Time Zone Names, in a JSON array, from timezones.json package

gen_IANA_time_zone_names_json.js

// Creating a JSON file, containing IANA Time Zone Names from timezones.json package.
// See this stackoverflow question: https://stackoverflow.com/a/69966796/

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Short version:
// const namesSet = new Set();
// require("timezones.json").forEach((tzDefinition) => tzDefinition.utc.forEach((tzName) => namesSet.add(tzName)));
// console.log(JSON.stringify([...namesSet].sort()));

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Long version:

const timezones = require("timezones.json");

function printSortedIANATimeZonesList(prettyPrint = false) {
	const namesSet = new Set();
	timezones
		.forEach((tzDefinition) => tzDefinition.utc
			.forEach((tzName) => namesSet.add(tzName)));
	
	const sortedNames = [...namesSet].sort();
	
	if (prettyPrint) {
		let pkgVersion = "";
		try { pkgVersion = `@${require("./node_modules/timezones.json/package.json").version}`; } catch(e) {}
		const isoTimeNow = new Date().toISOString();
		console.log(`// ${sortedNames.length} entries extracted from "timezones.json${pkgVersion}" package at ${isoTimeNow}`);
		console.log("[");
		// printing out line-by-line that terminal doesn't eat it
		sortedNames.forEach((name, i) => console.log(`\t"${name}"${i === sortedNames.length ? "" : ","}`));
		console.log("]");
	} else {
		console.log(JSON.stringify(sortedNames));
	}
}

printSortedIANATimeZonesList(true);