Benchmark: js-joda vs date-fns vs new Date() from ISO strings

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/npm/@js-joda/core@5.6.3/dist/js-joda.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/date-fns/1.9.0/date_fns.min.js"></script>

Tests:

js-joda (ZonedDateTime)
JSJoda.ZonedDateTime.parse('2025-01-09T12:36:53Z');
date-fns
dateFns.parse('2025-01-09T12:36:53Z')
new Date()
new Date('2025-01-09T12:36:53Z')
js-joda (just a date)
JSJoda.LocalDate.parse('2025-01-09')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
js-joda (ZonedDateTime)
date-fns
new Date()
js-joda (just a date)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0.1 Safari/605.1.15

Browser/OS: Safari 26 on Mac OS X 10.15.7

View result in a separate tab

new Date()

66.3M/s

date-fns

2.3M/s

js-joda (just a date)

196K/s

js-joda (ZonedDateTime)

112K/s

View exact numbers

Test name	Executions per second
✓ new Date()	66,338,152 Ops/sec
date-fns	2,278,514 Ops/sec
js-joda (just a date)	196,077 Ops/sec
js-joda (ZonedDateTime)	111,538 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The provided benchmark compares the performance of three different methods to parse date strings in JavaScript: js-joda, date-fns, and native JavaScript `Date`. This benchmark evaluates how efficiently each library or method can handle parsing dates from ISO 8601 formatted strings.

### Options Compared

1. **js-joda (ZonedDateTime)**
   - **Benchmark Definition:** `JSJoda.ZonedDateTime.parse('2025-01-09T12:36:53Z');`
   - **Library Purpose:** js-joda is a date and time library inspired by Java's Joda-Time, aiming to provide a more manageable and immutable way to work with dates and times in JavaScript. It includes features to handle time zones and various date-time formats.
   - **Performance Outcome:** 88,864.3 executions per second.

2. **date-fns**
   - **Benchmark Definition:** `dateFns.parse('2025-01-09T12:36:53Z')`
   - **Library Purpose:** date-fns is a lightweight utility library for manipulating dates in JavaScript. It provides a functional approach to date handling through pure functions that can be imported individually or as a whole.
   - **Performance Outcome:** 1,572,468.1 executions per second.

3. **Native JavaScript Date**
   - **Benchmark Definition:** `new Date('2025-01-09T12:36:53Z')`
   - **Library Purpose:** This method uses the built-in Date object in JavaScript, which is widely supported and easily accessible for standard date manipulations.
   - **Performance Outcome:** 27,491,350.0 executions per second.

4. **js-joda (LocalDate)**
   - **Benchmark Definition:** `JSJoda.LocalDate.parse('2025-01-09');`
   - **Performance Outcome:** 175,100.2 executions per second.

### Pros and Cons of Each Approach

- **js-joda:**
  - **Pros:**
    - Comprehensive time zone support and immutability.
    - More expressive API for date and time manipulation.
  - **Cons:**
    - Slower in performance compared to native JavaScript Date parsing.
    - Larger library size due to additional features.
  
- **date-fns:**
  - **Pros:**
    - Functional programming style allows for modular use and tree-shaking.
    - Good balance between performance and flexibility.
  - **Cons:**
    - More complex to work with for those unfamiliar with functional concepts.
  
- **Native JavaScript Date:**
  - **Pros:**
    - Extremely fast performance, being a built-in feature of the language.
    - Simple and straightforward for basic date operations.
  - **Cons:**
    - Lack of immutability; modifying a Date object can lead to unexpected results.
    - Limited in handling time zone differences without additional functionality.

### Other Considerations

**Impact on Real-World Scenarios:**
When choosing a date parsing method, the decision may hinge upon performance needs versus the complexity of date manipulations required. For highly performance-centric applications, native Date parsing may be favored. However, for applications that require tight control over date-time logic and time zones, js-joda or date-fns may be more suitable despite the performance trade-offs.

**Alternatives:**
Several other libraries provide similar functionalities:
- **Luxon:** Combines both date-time and I18n capabilities, providing an extensive API but larger footprint.
- **Moment.js:** Previously very popular but now considered a legacy solution in terms of performance and modern practices; it lacks the immutability and tree-shaking capabilities of newer libraries.

Overall, this benchmark highlights the critical trade-offs between performance and functionality within JavaScript date handling, helping developers make informed choices based on their specific use cases.

js-joda vs date-fns vs new Date() from ISO strings (version: 1)

Comparing performance of: `js-joda (ZonedDateTime) vs date-fns vs new Date() vs js-joda (just a date)`

Created: one year ago by: Guest

Go to the latest result

js-joda (ZonedDateTime)

date-fns

new Date()

js-joda (just a date)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

js-joda vs date-fns vs new Date() from ISO strings (version: 1)

Comparing performance of: js-joda (ZonedDateTime) vs date-fns vs new Date() vs js-joda (just a date)

Created: one year ago by: Guest

Go to the latest result

js-joda (ZonedDateTime)

date-fns

new Date()

js-joda (just a date)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

Related benchmarks

Comparing performance of: `js-joda (ZonedDateTime) vs date-fns vs new Date() vs js-joda (just a date)`