Benchmark: Map vs Object - the real test

Script Preparation code:

var map1 = new Map();
var obj1 = {};

map1.set(0, 5);
obj1[0] = 5;

var map2 = new Map();
var obj2 = {};
var arrString = [];
for (var i = 0; i < 10000000; i++) {
  arrString.push(i);
}
var arr = [1,2,3,null,5];
var a = 0, b = 0, c = 0, d = 0;

Tests:

Map lookup
map1.get('aaa');
Obj lookup
obj1['aaa'];
Map set
map2.set(arrString[a++], 1);
Obj set
obj2[arrString[b++]] = 1;
hasOwnProperty
obj1.hasOwnProperty('aaa');
has
map1.has('aaa');
delete
delete obj2[arrString[c++]];
remove
map2.delete(arrString[d++]);
array lookup
arr[2]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map lookup
Obj lookup
Map set
Obj set
hasOwnProperty
has
delete
remove
array lookup

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36

Browser/OS: Chrome 100 on Windows

View result in a separate tab

Test name	Executions per second
Map lookup	11828718.0 Ops/sec
Obj lookup	11614973.0 Ops/sec
Map set	1506301.5 Ops/sec
Obj set	2643046.2 Ops/sec
hasOwnProperty	11202681.0 Ops/sec
has	11518602.0 Ops/sec
delete	2406205.5 Ops/sec
remove	1833536.1 Ops/sec
array lookup	11589077.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what's being tested, the options compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark definition represents a JavaScript microbenchmark that tests the performance of various methods on objects and maps.

* `map1` and `obj1` are objects (JavaScript native data type) created using the `{}` syntax.
* `map2` is a Map object (a built-in JavaScript data structure), and `arrString` is an array filled with 10,000,000 indices from 0 to 9,999,999.

**Options Compared**

The benchmark compares the performance of various methods:

1. **Map Lookup (`map1.get('aaa')`) vs Object Lookup (`obj1['aaa']`)
	* Pros:
		+ Both are relatively fast and efficient.
	* Cons:
		+ `get()` method may be slower due to additional checks (e.g., key existence).
2. **Map Set (`map2.set(arrString[a++], 1)`) vs Object Set (`obj2[arrString[b++]] = 1`)
	* Pros:
		+ Both are efficient, but the Map set may be slightly faster due to its optimized implementation.
3. **hasOwnProperty()` (Object method) vs `has()` (Map method)
	* Pros:
		+ Both methods are fast and provide similar performance.
4. **delete` (`delete obj2[arrString[c++]]`) vs `remove()` (Map method)
	* Pros:
		+ Both methods are efficient, but the `remove()` method may be slightly faster due to its optimized implementation.
5. **Array Lookup (`arr[2]`)
	* Pros:
		+ Relatively fast and efficient.

**Other Considerations**

* The benchmark uses a large array `arrString` filled with 10,000,000 indices from 0 to 9,999,999. This is done to test the performance of each method under heavy loads.
* Both Map and object implementations use JavaScript's built-in equality checks for key existence.

**Library**

None mentioned in this benchmark definition.

No special JavaScript features or syntax used in this benchmark.

**Alternatives**

For similar microbenchmarks, consider:

1. jsPerf (discontinued)
2. Benchmark.js
3. Microbenchmarking libraries like fast-benchmark or benchmark-chromium

Keep in mind that different benchmarks may prioritize specific use cases or optimizations, so it's essential to choose the right tool for your needs.

This analysis should provide a good starting point for understanding this benchmark and its performance characteristics. If you have more questions or need further clarification, feel free to ask!

Related benchmarks:

Map vs Object - the real test (version: 19)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup vs Map set vs Obj set vs hasOwnProperty vs has vs delete vs remove vs array lookup

Created: 3 years ago by: Registered User

Jump to the latest result

Map lookup

Obj lookup

Map set

Obj set

hasOwnProperty

has

delete

remove

array lookup

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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