Benchmark: es6 map access with string vs symbol keys 12

Script Preparation code:

var eightSymbol = Symbol("eight")
var eightString = "eight";

var mapStringKeys = new Map([["one", true], ["two", true], ["three", true], ["four", true], ["five", true], ["six", true], ["seven", true], ["eight", true], ["nine", true], ["ten", true]]);
var mapStringAndSymbolKeys = new Map([["one", true], [Symbol("two"), true], ["three", true], [Symbol("four"), true], ["five", true], [Symbol("six"), true], ["seven", true], [eightSymbol, true], ["nine", true], [Symbol("ten"), true]]);

Tests:

Get string key from map with only string keys
var value = mapStringKeys.get(eightString);
Get symbol key from map with mixed string and symbol keys
var value = mapStringAndSymbolKeys.get(eightSymbol);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Get string key from map with only string keys
Get symbol key from map with mixed string and symbol keys

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 19_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 26 on iOS 19.0

View result in a separate tab

Test name	Executions per second
Get string key from map with only string keys	525480096.0 Ops/sec
Get symbol key from map with mixed string and symbol keys	506702720.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of what is tested in this benchmark.

**What is being tested?**

This benchmark tests the performance of accessing elements in a Map data structure using different approaches:

1. **String keys only**: The test case checks how fast it can retrieve values from a Map where all keys are strings.
2. **Mixed string and symbol keys**: The second test case tests how fast it can retrieve values from a Map where some keys are strings, while others are symbols.

**Options being compared**

Two main approaches are compared:

* **Using symbols as keys**: In JavaScript, symbols are unique and immutable, which makes them suitable for use as keys in Maps. This approach aims to take advantage of the potential performance benefits of using symbols over strings.
* **Using only string keys**: The traditional approach uses only strings as keys in the Map.

**Pros and cons of each approach**

* **Symbols as keys:**
	+ Pros:
		- Potentially faster access times due to symbol lookup being optimized by the engine.
		- Symbols are immutable, which can help reduce garbage collection overhead.
	+ Cons:
		- Fewer implementations support symbols as keys in older browsers or JavaScript engines.
		- Symbol lookups might be slower in some cases due to the additional complexity of symbol handling.
* **String keys only:**
	+ Pros:
		- Wide compatibility across different browsers and JavaScript engines.
		- Easier to implement and understand, with fewer potential pitfalls.
	+ Cons:
		- Might not take full advantage of potential performance benefits of symbols.

**Library or framework**

There is no explicit library mentioned in the benchmark definition. However, it's likely that the Map data structure is implemented by the JavaScript engine itself (e.g., V8 for Chrome).

**Special JS feature or syntax**

This benchmark doesn't explicitly test any special JavaScript features or syntax beyond what's standard in modern browsers.

**Other alternatives**

Some alternative approaches to accessing elements in a Map might include:

* Using objects with string properties as keys
* Using arrays with indices as keys
* Using a custom data structure designed specifically for this use case

However, these alternatives are not tested in this benchmark.

Related benchmarks:

es6 map access with string vs symbol keys 12 (version: 0)

Comparing performance of: Get string key from map with only string keys vs Get symbol key from map with mixed string and symbol keys

Created: 4 years ago by: Guest

Jump to the latest result

Get string key from map with only string keys

Get symbol key from map with mixed string and symbol keys

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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