Benchmark: Map vs Object 2 - MeasureThat.net

Script Preparation code:

var map = new Map();
var obj = {};

map.set('a', 5);
obj['a'] = 5;

var i = 0, count = 1000, a;

Tests:

Map lookup
for (i = 0; i < count; i++) { map.set('a',6); }
Obj lookup
for (i = 0; i < count; i++) { obj['a'] = 6; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map lookup
Obj lookup

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Windows

View result in a separate tab

Test name	Executions per second
Map lookup	24893.9 Ops/sec
Obj lookup	30766.3 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark definition and test cases for you.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmarking test case created on MeasureThat.net. The test case is designed to compare the performance of two data structures in JavaScript: `Map` and objects (specifically, arrays).

**Script Preparation Code**

The script preparation code initializes two variables:

* `map`: a new instance of the `Map` data structure.
* `obj`: an empty object (in JavaScript, objects are essentially arrays with string keys and values).
* Two lines set the value for key `'a'` in both `map` and `obj`, respectively.

**Html Preparation Code**

The HTML preparation code is null, which means that no HTML page or template is being used to run this benchmark. The test case only executes JavaScript code.

**Individual Test Cases**

There are two test cases:

1. **Map lookup**
	* Benchmark definition: `for (i = 0; i < count; i++) { map.set('a',6); }`
	* This test case iterates `count` times, setting the value of key `'a'` to `6` in a new instance of `Map`. The goal is to measure the time it takes to perform this operation.
2. **Obj lookup**
	* Benchmark definition: `for (i = 0; i < count; i++) { obj['a'] = 6; }`
	* This test case iterates `count` times, setting the value of key `'a'` to `6` in an empty object (`obj`). The goal is to measure the time it takes to perform this operation.

**Library**

The `Map` data structure used in this benchmark is a built-in JavaScript feature. It's a collection of key-value pairs that allows for fast lookups and efficient insertion/deletion operations.

**Special JS Features/Syntax**

There are no specific JavaScript features or syntax used in this benchmark, aside from the use of template literals (`var a = "";`) which is not unique to JavaScript but rather a feature of modern JavaScript.

**Pros and Cons of Different Approaches**

Here's a brief analysis of the two approaches:

1. **Map lookup**
	* Pros: `Map` provides fast lookups due to its hash-based implementation, making this approach suitable for large datasets.
	* Cons: Creating a new instance of `Map` on each iteration can be expensive in terms of memory allocation and garbage collection.
2. **Obj lookup**
	* Pros: Objects are more widely supported across browsers and platforms, making this approach more portable.
	* Cons: Object lookups can be slower due to the need for dynamic property lookup, which involves traversing the object's prototype chain.

**Other Considerations**

When running this benchmark, it's essential to consider the following:

* The size of the `count` variable will impact the performance difference between the two approaches.
* The specific JavaScript engine and browser being used can affect the performance results.
* The test case doesn't account for potential caching or optimization techniques that might be used by the browser or JavaScript engine.

**Alternatives**

If you'd like to create similar benchmarks, consider exploring other data structures in JavaScript, such as:

* Arrays
* Sets
* WeakMaps
* Proxy objects

You can also experiment with different iteration patterns, caching mechanisms, and optimization techniques to further explore the performance characteristics of each data structure.

Related benchmarks:

Map vs Object 2 (version: 0)

Set of map vs object

Comparing performance of: Map lookup vs Obj lookup

Created: 6 years ago by: Guest

Jump to the latest result

Map lookup

Obj lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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