Benchmark: WeakMap vs Symbol 2

Script Preparation code:

var to0 = {};
var to1 = {};
var wm = new WeakMap();
var sy = Symbol();
wm.set(to1, 1);
to1[sy] = 1;
window.r = 0

Tests:

WeakMap set
wm.set(to0, 1);
Symbol Property set
to0[sy] = 1;
WeakMap get
r = wm.get(to1);
Symbol Property get
r = to1[sy];
Symbol Property get (from own descriptor)
r = Object.getOwnPropertyDescriptor(to1, sy).value;
Symbol Property get (if hasOwn)
r = Object.hasOwn(sy) ? to1[sy] : undefined;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
WeakMap set
Symbol Property set
WeakMap get
Symbol Property get
Symbol Property get (from own descriptor)
Symbol Property get (if hasOwn)

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/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Windows

View result in a separate tab

Test name	Executions per second
WeakMap set	12726717.0 Ops/sec
Symbol Property set	13497805.0 Ops/sec
WeakMap get	6409639.0 Ops/sec
Symbol Property get	6529689.0 Ops/sec
Symbol Property get (from own descriptor)	4280086.0 Ops/sec
Symbol Property get (if hasOwn)	3817115.0 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 its test cases, explaining what's being tested, the pros and cons of each approach, and other considerations.

**Benchmark Definition JSON**

The benchmark definition is a simple JavaScript script that creates two objects (`to0` and `to1`) and sets up a WeakMap (`wm`) with a Symbol property (`sy`). The script then tests various operations on these objects using the WeakMap.

**Test Cases**

There are six test cases:

1. **WeakMap set**: `wm.set(to0, 1);`
	* This test case verifies that setting an entry in a WeakMap updates its `size` property correctly.
2. **Symbol Property set**: `to0[sy] = 1;`
	* This test case checks if setting a property on an object using a Symbol as the key works as expected.
3. **WeakMap get**: `r = wm.get(to1);`
	* This test case retrieves a value from the WeakMap associated with a given object and verifies its correctness.
4. **Symbol Property get**: `r = to1[sy];`
	* This test case accesses a property on an object using a Symbol as the key and checks if it returns the expected value.
5. **Symbol Property get (from own descriptor)**: `r = Object.getOwnPropertyDescriptor(to1, sy).value;`
	* This test case uses `Object.getOwnPropertyDescriptor` to access a property's descriptor and then retrieves its value using the `value` property of the descriptor.
6. **Symbol Property get (if hasOwn)**: `r = Object.hasOwn(sy) ? to1[sy] : undefined;`
	* This test case checks if the Symbol exists on an object by using `Object.hasOwn` and then accessing its value using the Symbol as a key.

**Options Compared**

The benchmark compares two approaches:

1. **WeakMap set**: Using a WeakMap to store data.
2. **Symbol Property set**: Using Symbols as keys for objects.

**Pros and Cons of Each Approach**

* **WeakMap set**:
	+ Pros:
		- Efficient memory management (garbage collection).
		- Fast lookups.
	+ Cons:
		- Limited functionality compared to other data structures like Maps or Sets.
		- May not be suitable for all use cases where Symbol-based access is desired.
* **Symbol Property set**:
	+ Pros:
		- Provides a unique and efficient way to identify objects in code.
		- Can be used with various data structures, such as objects, arrays, or Maps.
	+ Cons:
		- May not be suitable for cases where memory management is critical (e.g., in high-performance applications).
		- Some older browsers may not support Symbols.

**Other Considerations**

* **Browser Support**: The benchmark assumes the test runs on a modern browser that supports WeakMaps and Symbols.
* **Library Usage**: None of the test cases use any external libraries beyond what's built into JavaScript (e.g., `Object.getOwnPropertyDescriptor`).
* **JavaScript Features**: No special JavaScript features or syntax are used in these test cases.

**Alternatives**

Other alternatives for testing memory management, symbol-based access, or similar scenarios might include:

1. Benchmarking the performance of different data structures like Sets, Maps, or even custom implementations.
2. Testing the efficiency of various methods for garbage collection, such as reference counting or mark-and-sweep.
3. Comparing the execution speed of different algorithms for tasks involving symbol-based access or WeakMap usage.

Keep in mind that these alternatives might not directly address the specific use cases tested by the provided benchmark but can provide a broader understanding of performance and efficiency in JavaScript development.

Related benchmarks:

WeakMap vs Symbol 2 (version: 0)

Comparing performance of: WeakMap set vs Symbol Property set vs WeakMap get vs Symbol Property get vs Symbol Property get (from own descriptor) vs Symbol Property get (if hasOwn)

Created: one year ago by: Guest

Jump to the latest result

WeakMap set

Symbol Property set

WeakMap get

Symbol Property get

Symbol Property get (from own descriptor)

Symbol Property get (if hasOwn)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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