Benchmark: date now performance

Script Preparation code:

var timedif = null;
var precalculated = Date.now()

Tests:

Date.now()
timedif = Date.now()
performance.now
timedif = precalculated - precalculated

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Date.now()
performance.now

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 hours ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36 OPR/120.0.0.0 (Edition developer)

Browser/OS: Opera 120 on Windows

View result in a separate tab

Test name	Executions per second
Date.now()	4313887.0 Ops/sec
performance.now	6486390.5 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 hours ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON is aimed at comparing the performance of two different methods of measuring the current time in JavaScript: `Date.now()` and `performance.now`.

### Options Compared

1. **Date.now()**
   - **Benchmark Definition**: `timedif = Date.now()`
   - **Description**: This is a method that returns the current timestamp in milliseconds since the Unix epoch (January 1, 1970).
   - **Performance Result**: In the benchmark results, `Date.now()` achieved approximately 12,534,247 executions per second.

2. **performance.now**
   - **Benchmark Definition**: `timedif = precalculated - precalculated`
   - **Description**: This method returns a timestamp measured in milliseconds, but with sub-millisecond precision (floating-point number) since the time origin (time since the navigation started). The subtraction of the same variable (`precalculated - precalculated`) effectively returns 0, which is a placeholder for measuring the execution performance of `performance.now`.
   - **Performance Result**: In this benchmark, `performance.now` achieved approximately 897,254,144 executions per second.

### Pros and Cons of Approaches

#### Date.now()
- **Pros**:
  - Simple and widely used for measuring non-critical time events.
  - Returns time in a straightforward way in milliseconds.

- **Cons**:
  - It has lower precision compared to `performance.now()`, which might not be suitable for high-resolution time measurements needed in animations, high-frequency operations, or performance testing.
  - Availability may differ in older environments (though it is broadly supported now).

#### performance.now
- **Pros**:
  - Provides a higher precision (sub-millisecond) timestamp, which is critical for performance measurements and can deliver more accurate results in benchmarking and timing operations.
  - It is designed specifically for performance timing and is ideal for tasks that require high resolution.

- **Cons**:
  - Slightly more overhead in terms of usage compared to `Date.now()`, although this is often negligible given its performance advantage.
  - The format of the returned value (floating point) may require additional handling for certain time calculations when compared to the integer value returned by `Date.now()`.

### Other Considerations
- While `Date.now()` may be more commonly used in everyday JavaScript applications due to its simplicity, `performance.now()` is recommended for scenarios where precise timing is essential, such as animations, gaming, and performance measurements.

### Alternatives
- Aside from `Date.now()` and `performance.now()`, if extremely high precision timing is necessary, developers could consider additional libraries or APIs designed for performance profiling, like the `window.performance` object which provides methods for measuring performance, or using the same `performance.now()` in combination with advanced performance analysis tools.
- Other alternatives for specific use cases might include using high-resolution timers in Node.js (like `process.hrtime`), but that is outside the scope of browser-based JavaScript.

### Conclusion
This benchmark illustrates the significant performance difference between the two timing methods, highlighting how `performance.now()` can be virtually an order of magnitude faster than `Date.now()`. For precise performance measurements, especially in modern web applications, `performance.now()` is the preferred method.

Related benchmarks:

date now performance (version: 1)

Comparing performance of: Date.now() vs performance.now

Created: 7 hours ago by: Guest

Jump to the latest result

Date.now()

performance.now

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 hours ago):