Timestamps, dates, and time zones

What you will build

Distinguish seconds, milliseconds, UTC, and local display.

Understand the idea first

Distinguish seconds, milliseconds, UTC, and local display.

Build it step by step

const seconds = 1760000000;
const date = new Date(seconds * 1000);
const local = new Intl.DateTimeFormat(undefined, {
  dateStyle: 'medium',
  timeStyle: 'short',
}).format(date);
console.log(date.toISOString(), local);

1. Open the previous project and record its result.
2. Type the example and complete: Format one instant as ISO, local time, and Asia/Shanghai; explain the difference.
3. Change one input, predict, then verify.
4. Create and repair: Unix seconds need ×1000; do not store a formatted display string.

Read the important lines

• Distinguish seconds, milliseconds, UTC, and local display.
• Read input, processing, and output separately.
• Verify another input and an edge case.

Common mistakes and what to check

Practice without copying

Format one instant as ISO, local time, and Asia/Shanghai; explain the difference.

Completion check

• I produced the required visible result
• I can explain the input, processing, and output
• I tested normal, edge, and failure cases