Benchmark: WeakMap vs arrays read performance !!

Tests:

arrays
let keys = []; let values = []; let weakmap = new WeakMap(); for (let i = 0; i < 100000; i++) { const keyobj = { key: i }; const valobj = { val: `val_${i}` }; keys[i] = keyobj; values[i] = valobj; weakmap.set(keyobj, valobj); } for (let i = 0; i < 100000; i++) { const key = keys[i]; const val = values[key.key]; }
weakmap
let keys = []; let values = []; let weakmap = new WeakMap(); for (let i = 0; i < 100000; i++) { const keyobj = { key: i }; const valobj = { val: `val_${i}` }; keys[i] = keyobj; values[i] = valobj; weakmap.set(keyobj, valobj); } for (let i = 0; i < 100000; i++) { const key = keys[i]; const val = weakmap.get(key); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
arrays
weakmap

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 and its test cases.

**Benchmark Description**
The benchmark compares the performance of two approaches: using an array to store key-value pairs and accessing them, versus using a WeakMap data structure to store key-value pairs and accessing them.

**Options Compared**

1. **Arrays**: In this approach, arrays are used to store key-value pairs, where each key is an object with a `key` property and the corresponding value is stored in another object with a `val` property.
2. **WeakMap**: In this approach, a WeakMap data structure is used to store key-value pairs. A WeakMap is a type of Map that stores keys and values, but allows the garbage collector to free up memory if the key is no longer referenced elsewhere in the code.

**Pros and Cons**

* **Arrays**:
	+ Pros: Arrays are widely supported and can be easily extended with additional methods.
	+ Cons: When accessing an array element using its index, JavaScript needs to perform a linear search for the matching object, which can lead to slower performance compared to WeakMap.
* **WeakMap**:
	+ Pros: WeakMaps provide fast access times and are optimized for this use case.
	+ Cons: WeakMaps require V8 (the JavaScript engine used by Chrome) version 63.0 or later to support the `get` method with a single key.

**Library**
None of the test cases rely on any external libraries, as they only use built-in JavaScript features and data structures.

**Special JS Feature or Syntax**
The benchmark takes advantage of the following feature:

* **WeakMap**: Introduced in ECMAScript 2015 (ES6), WeakMaps provide a way to store key-value pairs where the key can be any object, including ones that may not survive beyond the current function call.
* **V8 JavaScript Engine optimizations**: To make use of WeakMap's performance benefits, the benchmark requires V8 version 63.0 or later.

**Other Alternatives**

1. **Object.prototype.keys() and Object.values() methods**: These methods can be used to iterate over array-like objects and retrieve their keys and values.
2. **Array.prototype.forEach() method**: This method can be used to iterate over arrays and perform an action for each element.
3. **Map data structure**: Introduced in ECMAScript 2015 (ES6), Map is a built-in data structure that provides fast key-value pair lookups.

In summary, the benchmark compares the performance of two approaches: using an array to store key-value pairs and accessing them versus using a WeakMap data structure to store key-value pairs and accessing them. The results are expected to show which approach is faster in terms of execution per second.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser/OS: Chrome 103 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
arrays	35.9 Ops/sec
weakmap	37.0 Ops/sec

Related benchmarks:

WeakMap vs arrays read performance !! (version: 0)

Comparing performance of: arrays vs weakmap

Created: 2 years ago by: Guest

Jump to the latest result

arrays

weakmap

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):