Benchmark: loop test 122 - MeasureThat.net

Script Preparation code:

var arr = [...Array(1e5)];

Tests:

for
for(let i = 0; i < arr.length; i++) { // }
for in
for(let i in arr) { // }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
for in

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what's being tested.

**Benchmark Definition:**

The provided JSON represents a benchmark with two main components:

1. **Script Preparation Code**: The script preparation code is used to prepare the environment for the benchmark. In this case, it creates an array `arr` with 100,000 elements using the expression `Array(1e5)`. This step is crucial as it sets up the input data that will be processed in the subsequent test cases.
2. **Html Preparation Code**: The html preparation code is not used in this benchmark definition. However, it's worth noting that some benchmarks might include HTML-related setup to ensure consistency across different browsers.

**Test Cases:**

The benchmark includes two individual test cases:

1. **"for"`**: This test case measures the performance of a traditional `for` loop.
2. **"for in"`**: This test case measures the performance of an older `for...in` loop syntax, which is less efficient than modern `for` loops.

**Comparison:**

In this benchmark, two different `for` loop approaches are compared:

* Traditional `for` loop (`"for"`)
* Older `for...in` loop syntax (`"for in"`)

The main difference between these two approaches is the way the loop variable `i` is declared. In a traditional `for` loop, the loop variable is explicitly declared using `let i = 0;`. In contrast, an older `for...in` loop uses the `in` keyword to iterate over the array's properties.

**Pros and Cons:**

* **Traditional `for` loop (`"for"`)**:
	+ Pros:
		- More efficient and readable
		- Widely supported across browsers
	+ Cons:
		- Less flexible than older syntax
* **Older `for...in` loop syntax (`"for in"`)**:
	+ Pros:
		- Can be used in situations where array indices are not known or are dynamic
	+ Cons:
		- Less efficient and less readable than traditional `for` loops
		- Not widely supported across browsers (although some older versions of Safari might still work)

**Library:**

There is no explicit library mentioned in the benchmark definition. However, it's worth noting that modern JavaScript engines often rely on libraries like V8 (used by Chrome) or SpiderMonkey (used by Firefox) to optimize and execute JavaScript code.

**Special JS feature/syntax:**

None of the provided test cases use any special JavaScript features or syntax beyond the differences mentioned between traditional `for` loops and older `for...in` loop syntax.

Related benchmarks:

loop test 122 (version: 0)

Comparing performance of: for vs for in

Created: 5 years ago by: Registered User

Jump to the latest result

for

for in

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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