How do you implement a task scheduler with cron-like functionality?

Question

Accepted Answer

**Task scheduler** — run tasks on a schedule.

```javascript
const schedule = require("node-schedule");

// Run every day at 9 AM
schedule.scheduleJob("0 9 * * *", async () => {
    console.log("Running daily report...");
    await generateDailyReport();
});

// Run every 5 minutes
schedule.scheduleJob("*/5 * * * *", async () => {
    await syncData();
});

// Custom scheduler with persistence
class TaskScheduler {
    constructor(db) {
        this.db = db;
        this.jobs = new Map();
    }

async schedule(name, cronExpression, handler) {
        const job = schedule.scheduleJob(cronExpression, async () => {
            try {
                await handler();
                await this.db.saveRun(name, "success");
            } catch (err) {
                await this.db.saveRun(name, "failed", err.message);
            }
        });

this.jobs.set(name, job);
        await this.db.saveSchedule(name, cronExpression);
    }

cancel(name) {
        const job = this.jobs.get(name);
        if (job) job.cancel();
        this.jobs.delete(name);
    }

async restoreAll() {
        const schedules = await this.db.getAllSchedules();
        for (const s of schedules) {
            await this.schedule(s.name, s.cron, s.handler);
        }
    }
}
```

Node.js: How do you implement a task scheduler with cron-like functionality?