Benchmark: Every time parse date or second loop with date parse

Script Preparation code:

var data = []
var out

for (let i = 0; i < 100; i++)
  data.push({ date: new Date(Math.round(Date.now() * Math.random())).toISOString(), id: Math.floor(i / 25) })
for (let i = 0; i < 100; i++)
  data.push({ date: new Date(Math.round(Date.now() * Math.random())).toISOString(), id: Math.round(Math.random() * 5) })

Tests:

Every time date parse
out = [] for (let i = 0; i < data.length; i++) { const last = out[out.length - 1] const { id, date } = data[i] if (last && last.id === id) last.date = new Date(date) else out.push({ id, date: new Date(date) }) }
Parse in second loop
out = [] for (let i = 0; i < data.length; i++) { const last = out[out.length - 1] const { id, date } = data[i] if (last && last.id === id) last.date = date else out.push({ id, date: date }) } for (let i = 0; i < out.length; i++) out[i].date = new Date(out[i].date)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Every time date parse
Parse in second loop

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what's being tested.

**Benchmark Definition**

The provided Benchmark Definition represents two test cases:

1. **"Every time date parse"`**: This test case is designed to measure the performance of updating the `date` property of an object when its value is already present in the output array.
2. **"Parse in second loop"`**: This test case measures the performance of parsing and pushing a new object into the output array, which includes formatting the `date` property as a string.

**Options compared**

The two options being compared are:

1. Updating the `date` property when it's already present in the output array.
2. Parsing and pushing a new object into the output array without updating the `date` property.

**Pros and Cons of each approach**

**Option 1: "Every time date parse"`**

Pros:

* May be more efficient if the `date` property is always needed, as it reduces the need for subsequent parsing operations.
* Could potentially avoid unnecessary updates to the object's properties.

Cons:

* May result in slower performance due to repeated parsing and formatting of the `date` property.
* Might lead to increased memory usage due to storing redundant date values.

**Option 2: "Parse in second loop"`**

Pros:

* Can potentially be faster since it only requires a single parse operation for each new object added to the output array.
* Reduces the number of updates needed, which might conserve memory and improve overall performance.

Cons:

* May lead to slower performance if the `date` property needs to be parsed multiple times (e.g., when updating an existing value).
* Could result in increased memory usage due to storing multiple date values.

**Library:**

The provided benchmark code uses JavaScript's native `Date` object, which is a built-in library. The purpose of this library is to provide a standard way to represent dates and timestamps in JavaScript.

**Special JS feature or syntax:**

There are no special JavaScript features or syntaxes used in the provided benchmark code that would require explanation beyond basic understanding of JavaScript programming concepts.

**Other alternatives:**

To measure similar performance characteristics, alternative approaches could include:

1. Using a different data structure (e.g., an array of objects with timestamps) and parsing logic.
2. Utilizing a separate utility function for date formatting and manipulation.
3. Implementing a custom solution using a caching mechanism to reduce the number of parse operations.

These alternatives would require significant changes to the benchmark code, but could potentially provide valuable insights into performance differences under different conditions.

In summary, the provided benchmark measures the performance difference between updating an existing `date` property versus parsing and pushing a new object with a formatted `date` property. The choice between these approaches depends on specific use cases and requirements.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:121.0) Gecko/20100101 Firefox/121.0

Browser/OS: Firefox 121 on Windows

View result in a separate tab

Test name	Executions per second
Every time date parse	24515.7 Ops/sec
Parse in second loop	51158.6 Ops/sec

Related benchmarks:

Every time parse date or second loop with date parse (version: 0)

Comparing performance of: Every time date parse vs Parse in second loop

Created: one year ago by: Registered User

Jump to the latest result

Every time date parse

Parse in second loop

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):