Job Scheduler Status Dashboard

Build a status dashboard utility for scheduled jobs that displays when jobs will execute next and provides timing information.

Requirements

Your implementation should:

1. Create a function getJobStatus(cronExpression, timezone) that takes a cron expression string and optional timezone string, and returns an object containing:

   • next: the next execution time
   • upcoming: an array of the next 5 execution times
   • millisecondsUntilNext: the number of milliseconds until the next execution

2. Create a function getJobHistory(job) that takes an active job object and returns the last execution time (if available)

3. Create a function formatJobSummary(cronExpression, timezone) that returns a human-readable string showing:

   • The cron expression
   • The timezone (or "local" if not specified)
   • The next execution time
   • Time remaining until next execution (in seconds)

Implementation Details

• Support standard cron expressions (5-field format)
• Handle timezone-aware scheduling
• All functions should handle cases where the job has not run yet
• Times should be returned in appropriate formats for display

Dependencies { .dependencies }

cron { .dependency }

Provides job scheduling and cron expression handling capabilities.

Test Cases

Test 1: Get Status for Hourly Job { .test }

File: scheduler.test.js

const { getJobStatus } = require('./scheduler');

const status = getJobStatus('0 * * * *'); // Run at minute 0 of every hour
console.assert(status.next !== undefined, 'Should return next execution time');
console.assert(Array.isArray(status.upcoming), 'Should return upcoming times array');
console.assert(status.upcoming.length === 5, 'Should return 5 upcoming times');
console.assert(status.millisecondsUntilNext > 0, 'Should return positive milliseconds');
console.log('Test 1 passed');

Test 2: Get Status with Timezone { .test }

File: scheduler.test.js

const { getJobStatus } = require('./scheduler');

const status = getJobStatus('30 14 * * *', 'America/New_York'); // 2:30 PM EST daily
console.assert(status.next !== undefined, 'Should return next execution time');
console.assert(status.upcoming.length === 5, 'Should return 5 upcoming times');
console.log('Test 2 passed');

Test 3: Format Job Summary { .test }

File: scheduler.test.js

const { formatJobSummary } = require('./scheduler');

const summary = formatJobSummary('0 12 * * *', 'UTC'); // Noon UTC daily
console.assert(typeof summary === 'string', 'Should return a string');
console.assert(summary.includes('0 12 * * *'), 'Should include cron expression');
console.assert(summary.includes('UTC'), 'Should include timezone');
console.log('Test 3 passed');