Formatting Dates
Display dates with toLocaleDateString options.
Formatting Dates is a free JavaScript Academy lesson on CoddyKit. This is lesson 3 of 4. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the JavaScript Academy learning path, and your progress syncs across the web and the CoddyKit app. The JavaScript Academy course includes 4 lessons in total.
Formatting Dates
JavaScript provides several built-in methods to turn a date into readable text, from locale-aware output to standardized ISO strings.
const d = new Date(Date.UTC(2024, 0, 15))
console.log(d.toISOString())toISOString
toISOString returns a standardized string in UTC, ideal for storage and data exchange because it is unambiguous.
const d = new Date(Date.UTC(2024, 0, 15, 10, 30, 0))
console.log(d.toISOString())Slicing the ISO String
The ISO string places the date first, so you can slice off the first ten characters to get just the calendar date.
const d = new Date(Date.UTC(2024, 0, 15))
console.log(d.toISOString().slice(0, 10))toLocaleDateString
toLocaleDateString formats the date portion using a locale, producing region-appropriate output.
const d = new Date(Date.UTC(2024, 0, 15))
const text = d.toLocaleDateString("en-US", { timeZone: "UTC" })
console.log(typeof text)Locale Argument
The first argument is a locale tag like en-US or de-DE, which changes the order and separators of the formatted date.
const d = new Date(Date.UTC(2024, 0, 15))
const us = d.toLocaleDateString("en-US", { timeZone: "UTC" })
const iso = d.toISOString().slice(0, 10)
console.log(typeof us, iso)Formatting Options
An options object lets you choose how each part appears, such as a long month name or a numeric year.
const d = new Date(Date.UTC(2024, 0, 15))
const text = d.toLocaleDateString("en-US", { year: "numeric", month: "long", day: "numeric", timeZone: "UTC" })
console.log(typeof text)toLocaleTimeString
toLocaleTimeString formats only the time portion, again respecting the locale and any options you provide.
const d = new Date(Date.UTC(2024, 0, 15, 14, 5, 0))
const text = d.toLocaleTimeString("en-US", { timeZone: "UTC" })
console.log(typeof text)toLocaleString
toLocaleString combines both date and time into a single localized string.
const d = new Date(Date.UTC(2024, 0, 15, 9, 0, 0))
const text = d.toLocaleString("en-US", { timeZone: "UTC" })
console.log(typeof text)toDateString
toDateString gives a fixed, human-readable English date without locale options, useful for quick logging.
const d = new Date(Date.UTC(2024, 0, 15))
console.log(typeof d.toDateString())Intl.DateTimeFormat
For repeated formatting, Intl.DateTimeFormat creates a reusable formatter object, which is more efficient than calling locale methods many times.
const fmt = new Intl.DateTimeFormat("en-US", { timeZone: "UTC", dateStyle: "medium" })
const d = new Date(Date.UTC(2024, 0, 15))
console.log(typeof fmt.format(d))Choosing a Format
Use ISO strings for storage and APIs, and locale methods for display to users in their region. Keep these concerns separate.
const d = new Date(Date.UTC(2024, 0, 15))
console.log(d.toISOString().slice(0, 10))Quick Check
Test your formatting knowledge.
Recap
Recap: Pick the right formatting method for the job.
- toISOString for storage and APIs
- toLocaleDateString and friends for user display
- Options control month names and number styles
- Intl.DateTimeFormat is efficient for repeated formatting
const d = new Date(Date.UTC(2024, 0, 15))
console.log(d.toISOString().slice(0, 10))
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Frequently Asked Questions
Is the “Formatting Dates” lesson free?
Yes — any 3 lessons of the JavaScript Academy learning path, including “Formatting Dates”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The JavaScript Academy course includes 4 lessons in total.
What will I learn in “Formatting Dates”?
Display dates with toLocaleDateString options. You practise JavaScript Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start JavaScript Academy?
No prior experience is required. JavaScript Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 4.
How long does the “Formatting Dates” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this JavaScript Academy lesson?
Yes. Every JavaScript Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.