Benchmark: array size 5 - MeasureThat.net

Tests:

undefined
let myArray = []; for (let i=0; i<102400; i++) { myArray.push("foo" + i); }
defined
let myArray = new Array(102400); for (let i=0; i<102400; i++) { myArray[i] = "foo" + i; }
defined (wrong)
let myArray = new Array(1024); for (let i=0; i<102400; i++) { myArray.push("foo" + i); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
undefined
defined
defined (wrong)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

I'll explain the benchmark test cases and provide insights into the options being compared, pros and cons of each approach, and other considerations.

**Benchmark Definition**
The benchmark definition provided is for creating an array with 1024 elements using two different methods:

1. **let myArray = new Array(102400);`**: This creates a new array with 102400 elements in the script preparation code.
2. **let myArray = [];\r\nfor (let i=0; i<102400; i++) {\r\n  myArray.push(\"foo\" + i);\r\n}`: This creates an array by pushing 102400 elements using a loop.

**Options being compared**

Two main options are being compared:

1. **Preallocating memory**: Creating an array with a specific size (option 1) versus creating an array without preallocating memory and then adding elements dynamically (option 2).
2. **Direct assignment vs. push method**: The first option uses direct assignment to initialize the array, while the second option uses the `push()` method.

**Pros and Cons of each approach**

**Preallocating memory:**

Pros:

* Can be faster for large arrays since memory is allocated upfront
* Can reduce the overhead of dynamic allocation

Cons:

* Can lead to memory fragmentation if elements are added or removed frequently
* May not perform well on low-memory devices or systems with limited heap space

**Dynamic allocation using push method:**

Pros:

* Allows for more flexibility in adding or removing elements dynamically
* Can be beneficial when working with varying array sizes

Cons:

* May lead to slower performance due to the overhead of dynamic allocation
* Can cause memory fragmentation if not managed carefully

**Other considerations**

* **JavaScript engine optimization**: Some JavaScript engines, like SpiderMonkey (used by Firefox), have optimized their garbage collection and memory management algorithms to reduce the impact of preallocating memory.
* **Array length limits**: In modern JavaScript engines, there are limits on array lengths, typically around 2^32 - 1. Exceeding these limits can lead to errors or performance issues.

**Library usage**
There is no library explicitly mentioned in the benchmark definition. However, it's worth noting that some libraries like Lodash or Underscore.js provide utility functions for working with arrays, which might be used indirectly by optimizing JavaScript code generated by the benchmark.

**Special JS features or syntax**
No special JavaScript features or syntax are being tested in this benchmark. The focus is on comparing different approaches to creating an array.

**Other alternatives**

Alternative approaches to testing this benchmark could include:

* Using a different data structure, such as a linked list or a stack
* Adding more complex operations to the script preparation code (e.g., sorting, filtering)
* Using multiple browsers or devices with varying hardware configurations

These alternative approaches would help validate the results and provide a more comprehensive understanding of the performance characteristics of JavaScript array creation.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.79 Safari/537.36

Browser/OS: Chrome 67 on Windows 7

View result in a separate tab

Test name	Executions per second
undefined	26.9 Ops/sec
defined	38.7 Ops/sec
defined (wrong)	28.2 Ops/sec

Related benchmarks:

array size 5 (version: 0)

Comparing performance of: undefined vs defined vs defined (wrong)

Created: 6 years ago by: Guest

Jump to the latest result

undefined

defined

defined (wrong)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):