Benchmark: Symbol vs String property square bracketvv

Script Preparation code:

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

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

Latest run results:

No previous run results

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

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I'd be happy to explain what's being tested in this benchmark.

**What is being tested:**

The benchmark measures the performance difference between accessing a property using a `Symbol` (a unique and immutable identifier) versus a string literal (`"key"`). Both approaches are used to set a value on an object `foo`.

**Options compared:**

There are two options being compared:

1. **Accessing a property using a `Symbol`:** This involves creating a new symbol using the `Symbol()` function and using it as the key to access a property of the `foo` object.
2. **Accessing a property using a string literal:** This involves using a plain string literal (`"key"`) as the key to access a property of the `foo` object.

**Pros and Cons:**

* **Symbol:** Using a symbol has several advantages:
	+ Symbols are unique and cannot be duplicated, which makes them ideal for use as keys in objects.
	+ Symbols are immutable, meaning their value cannot be changed after creation.
	+ Symbols can help avoid collisions with other keys that might have the same value.
* However, using symbols also means:
	+ They are not supported by older browsers or JavaScript engines.
	+ Symbols are not cached, which means they need to be recalculated every time they are needed.

On the other hand, string literals:

* Are widely supported by most browsers and JavaScript engines.
* Are cached, meaning their value is only calculated once when the code is first executed.
* Can be faster for simple lookups since strings are often cached in the browser's memory.

However, using string literals also means that there is a small chance of collisions (when two different keys happen to have the same value), although this is extremely rare and typically not a concern.

**Other considerations:**

The benchmark also includes another test case where the `str` variable is used as the key instead of `"key"`. This introduces an additional variable that may impact performance, so it's interesting to see how the results compare between these three scenarios.

**Library usage:**

There are no libraries being used in this benchmark. The code only relies on built-in JavaScript features.

**Special JS feature or syntax:**

The `Symbol()` function and string literals are standard JavaScript features that have been available since ECMAScript 2015 (ES6). There are no other special features or syntax being tested here.

**Other alternatives:**

If you want to explore alternative approaches, here are a few options:

1. **Using a custom data structure:** Instead of using symbols or string literals as keys, you could create a custom data structure that is optimized for fast lookups.
2. **Caching the results:** You could cache the results of the benchmark runs so that they can be reused instead of recalculated every time.
3. **Comparing with other approaches:** Depending on your specific use case, you might want to compare the performance of using symbols or string literals against other approaches, such as using numerical keys or a hash table.

I hope this explanation helps!

Related benchmarks:

Symbol vs String property square bracketvv (version: 0)

Comparing performance of: Symbol vs String

Created: 3 years ago by: Guest

Jump to the latest result

Symbol

String

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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