Benchmark: Math.random vs Date.now

Tests:

Math.random
Math.random()
Date.now
Date.now()

Historical Performance Data aggregated from 39 community runs

Desktop Results:

Chrome 32 runs

Math.random

69.6M/s

Date.now

20.0M/s

Fastest: Math.random (3.5x faster)

View exact numbers

✓ Math.random: 69,644,008 ops/sec
• Date.now: 19,956,084 ops/sec

Firefox 7 runs

Math.random

1063.0M/s

Date.now

16.0M/s

Fastest: Math.random (66.4x faster)

View exact numbers

✓ Math.random: 1,063,022,656 ops/sec
• Date.now: 16,009,232 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Math.random
Date.now

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Windows

View result in a separate tab

Math.random

68.8M/s

Date.now

27.9M/s

View exact numbers

Test name	Executions per second
✓ Math.random	68,750,400 Ops/sec
Date.now	27,915,438 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and considered.

**Benchmark Overview**

The main goal of this benchmark is to determine which method, `Math.random()` or `Date.now()`, is better for generating unique keys in JavaScript. Unique keys are often required in web applications, especially when dealing with cookies, tokens, or other identification mechanisms.

**Options Compared**

Two options are being compared:

1. **`Math.random()`**: This function generates a random number between 0 (inclusive) and 1 (exclusive). While it's not designed for generating unique keys, it can be used in some cases.
2. **`Date.now()`**: This function returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00 UTC).

**Pros and Cons**

**`Math.random()`**:

Pros:

* Easy to use
* Fast execution time

Cons:

* Not designed for generating unique keys
* May produce duplicate values due to seeding issues (e.g., using `Math.random()` in a loop without re-seeding)

**`Date.now()`**:

Pros:

* Designed for generating unique timestamps
* Less prone to duplicates compared to `Math.random()`

Cons:

* May not be suitable for all use cases, especially those requiring non-integer values or very high precision

**Other Considerations**

When choosing between these two options, consider the following factors:

* **Uniqueness**: If you need a guaranteed unique key, `Date.now()` is generally a better choice. However, if you're working with a limited range of possible keys (e.g., strings), `Math.random()` might be sufficient.
* **Precision**: If your application requires high precision or non-integer values, `Date.now()` is likely a better option.
* **Performance**: Both methods are relatively fast, but `Date.now()` is generally more efficient due to its native implementation.

**Library and Special JS Features**

There is no library mentioned in the provided benchmark definition. However, it's worth noting that other libraries like `crypto` or `uuid` might be used for generating unique keys in real-world applications.

No special JavaScript features are used in this benchmark beyond what's considered standard.

**Alternatives**

Other alternatives for generating unique keys include:

* **`crypto.randomBytes()`**: Generates a random array of bytes, suitable for cryptographic purposes.
* **`uuid()`**: Generates a universally unique identifier (UUID) string.
* **`Web Storage` or `Cookies`:** Use the browser's storage mechanism to store and retrieve values as unique identifiers.

These alternatives offer different trade-offs between uniqueness, precision, performance, and security, depending on the specific use case.

Math.random vs Date.now (version: 0) Benchmark.js

Which is best for generating a unique key?

Comparing performance of: `Math.random vs Date.now`

Created: 4 years ago by: Guest

Go to the latest result

Math.random

Date.now

Historical Performance Data aggregated from 39 community runs

Desktop Results:

Chrome 32 runs

Firefox 7 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

Math.random vs Date.now (version: 0) Benchmark.js

Which is best for generating a unique key?

Comparing performance of: Math.random vs Date.now

Created: 4 years ago by: Guest

Go to the latest result

Math.random

Date.now

Historical Performance Data aggregated from 39 community runs

Desktop Results:

Chrome 32 runs

Firefox 7 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

Related benchmarks

Comparing performance of: `Math.random vs Date.now`