Script to announce Tabata intervals

tabata.cjs

#!/usr/bin/env node

const os = require("os");

if (os.platform() !== "darwin") {
	console.error("This script only works with macOS.");
	process.exit(1);
}

const { spawn } = require("child_process");

let [time, rest, reps] = process.argv.slice(2);
time ||= 20;
rest ||= 10;
reps ||= 8;

let count = 0;

const resetCount = () => (count = 0);

const say = message => spawn("say", ["-v", "samantha", message]);

const run = (t, r, limit) => {
	say(count === limit - 1 ? `last set` : `go`);
	if (count < limit - 1) {
		setTimeout(() => {
			count = count + 1;
			say("rest");
			setTimeout(() => {
				run(t, r, limit);
			}, rest * 1000);
		}, t * 1000);
	} else {
		setTimeout(() => say("done"), t * 1000);
		resetCount();
	}
};

run(time, rest, reps);