Benchmark: WeakMap vs Symbol Property v2

Script Preparation code:

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

Tests:

WeakMap set
wm.set(to0, 1);
Symbol Property set
to0[sy] = 1;
WeakMap get
let r = wm.get(to1);
Symbol Property get
let r = to1[sy];
WeakMap has
let r = wm.has(to1);

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
WeakMap has

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 dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The provided JSON represents a benchmark that tests the performance of `WeakMap` and `Symbol Property` (also known as "symbol properties" or "property descriptors") in JavaScript.

**What is tested?**

The benchmark compares the performance of three different approaches:

1. **WeakMap.set()**: This method checks if a key exists in the map and, if not, inserts it.
2. **Symbol Property set**: Using a `Symbol` property to store values in an object. The `Symbol` property is a unique identifier for a property that cannot be used as a regular property name.
3. **WeakMap has()**: This method checks if a key exists in the map.

**Options compared**

The benchmark compares the performance of these three approaches:

* WeakMap.set(): checks if the key exists and inserts it if not
* Symbol Property set: uses a unique identifier to store values, without checking for existence
* WeakMap has(): checks if the key exists

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

1. **WeakMap.set()**
	* Pros:
		+ Efficient way to check if a key exists and insert it if not.
		+ Can be used with any type of value (numbers, strings, objects, etc.)
	* Cons:
		+ May perform additional work for simple existence checks
2. **Symbol Property set**
	* Pros:
		+ Fast and efficient way to store values without checking for existence
		+ Can be useful in certain scenarios where existence is not necessary
	* Cons:
		+ Only works with numeric `Symbol` values (not strings or objects)
		+ May lead to unexpected behavior if used incorrectly
3. **WeakMap has()**
	* Pros:
		+ Fast and efficient way to check if a key exists
	* Cons:
		+ Only checks for existence, not insertion

**Library**

There is no specific library mentioned in the benchmark definition. The benchmark only uses built-in JavaScript features: `WeakMap`, `Symbol` properties, and basic object literals.

**Special JS feature or syntax**

The benchmark uses the following special features:

* **WeakMap**: a type of map that allows for efficient existence checks
* **Symbol Property**: a unique identifier for a property that cannot be used as a regular property name

**Other alternatives**

If you were to write this benchmark from scratch, you might consider using other approaches, such as:

* Using a hash table or an object with fast existence checks (e.g., `Object.hasOwn()` or `Map.prototype.has()`)
* Using a library like LRU Cache or a similar caching mechanism
* Optimizing the benchmark for specific use cases or performance requirements

Keep in mind that these alternatives might not be as straightforward to implement and may require more expertise in JavaScript performance optimization.

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 12; M2101K9G) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 107 on Android

View result in a separate tab

Test name	Executions per second
WeakMap set	2677249.5 Ops/sec
Symbol Property set	2861349.0 Ops/sec
WeakMap get	2725366.5 Ops/sec
Symbol Property get	2871802.5 Ops/sec
WeakMap has	2597251.8 Ops/sec

Related benchmarks:

WeakMap vs Symbol Property v2 (version: 0)

Comparing performance of: WeakMap set vs Symbol Property set vs WeakMap get vs Symbol Property get vs WeakMap has

Created: one year ago by: Guest

Jump to the latest result

WeakMap set

Symbol Property set

WeakMap get

Symbol Property get

WeakMap has

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):