Benchmark: Symbol vs String property square bracket

Script Preparation code:

var foo = {};
var sym = Symbol("key");
var str = "key";

Tests:

Symbol
foo[sym] = 1;
String
foo[str] = 1;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Symbol
String

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark is testing how fast JavaScript engines can access properties on an object using either a `Symbol` property or a string property. The benchmark is comparing the performance of these two approaches.

**Options Compared**

There are only two options being compared:

1. **Symbol Property**: Using a `Symbol` property to access the value.
2. **String Property**: Using a string property (e.g., "key") to access the value.

**Pros and Cons of Each Approach**

* **Symbol Property**
	+ Pros:
		- Unique identifier, which can prevent conflicts with other properties.
		- Can be used as a key in `Object.prototype.hasOwnProperty()` checks for performance optimization.
	+ Cons:
		- May not be supported by older JavaScript engines or browsers.
		- Not human-readable, making it harder to debug.
* **String Property**
	+ Pros:
		- Widely supported across older and newer JavaScript engines and browsers.
		- Human-readable, making it easier to debug.
	+ Cons:
		- May cause conflicts with other properties if not used carefully.

**Library and Purpose**

In this benchmark, the `Symbol` function is being used to create a new symbol property. The `Symbol` function was introduced in ECMAScript 2015 (ES6) as a way to create unique identifiers that can be used as property keys or function signatures.

**Special JS Feature/ Syntax**

The benchmark uses the `Symbol` function, which is a special feature introduced in ES6. It's not a standard JavaScript syntax, but rather a new construct introduced by the language specification. This means that older JavaScript engines and browsers may not support it natively.

**Other Alternatives**

If you wanted to write this benchmark yourself, here are some alternatives:

1. Use `Object.create(null)`: Instead of using a symbol property, you could use an object created with `Object.create(null)` as the test subject.
2. Use `Map` or `WeakMap`: If you're targeting modern browsers that support `Map` and `WeakMap`, you could use these data structures to store the keys and values.
3. Write a custom property accessor: You could write a custom property accessor function to test how JavaScript engines handle property access.

Keep in mind that implementing this benchmark yourself would require writing custom code to replicate the exact behavior of the `Symbol` property.

For your reference, here's some sample code for each alternative:

* Using `Object.create(null)`: `var foo = Object.create(null); foo[sym] = 1;`
* Using `Map`: `const map = new Map(); map.set(symmetricKey, value);`
* Writing a custom property accessor: You would need to write a function that takes the property key and value as arguments and performs the desired operation.

Latest run results:

Run details: (Test run date: 7 days ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_7_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.8 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 17 on iOS 17.7.1

View result in a separate tab

Test name	Executions per second
Symbol	6173637.0 Ops/sec
String	6065890.0 Ops/sec

Related benchmarks:

Symbol vs String property square bracket (version: 0)

Comparing performance of: Symbol vs String

Created: 4 years ago by: Guest

Jump to the latest result

Symbol

String

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):