Benchmark: Access time Map vs Object

Script Preparation code:

const myVar = 'test'
const myMap = new Map();
const myObj = {};

for(let i = 0; i < 100; i++) {
  const newVar = `${myVar}${i}`;
  myMap.set(newVar, 0);
  myObj[newVar] = 0;
}

const length = 100000000;

Tests:

Object access
for (let i=0; i < length; i++) { myObj.test; }
Map access
for (let i=0; i < length; i++) { myMap.get('test'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object access
Map access

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36 Edg/142.0.0.0

Browser/OS: Chrome 142 on Windows

View result in a separate tab

Test name	Executions per second
Object access	0.5 Ops/sec
Map access	0.3 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 world of JavaScript microbenchmarks on MeasureThat.net.

The provided JSON represents two benchmark definitions for comparing the performance of accessing objects and maps in JavaScript. We'll explore each benchmark individually, highlighting what's being tested, the options compared, pros and cons, library usage, special JS features or syntax, and alternative approaches.

**Benchmark 1: Access time Map vs Object**

This benchmark compares the performance of accessing an object (`myObj`) versus a map (`myMap`). The script preparation code initializes both data structures with 100 key-value pairs. The benchmark definition measures the execution time for a single iteration of a loop that accesses each key in `myObj` or retrieves a value from `myMap`.

**Options compared:**

* Object access (via dot notation, e.g., `myObj.test`)
* Map access (via `get()` method, e.g., `myMap.get('test')`)

**Pros and Cons:**

* **Object Access:**
	+ Pros:
		- Familiar syntax for most developers
		- Can be optimized with caching or memoization techniques
	+ Cons:
		- May lead to slower performance due to the overhead of creating an object literal and accessing its properties
* **Map Access:**
	+ Pros:
		- Generally faster than object access, especially for large datasets
		- Provides a more flexible way to store and retrieve data (e.g., with iteration or iteration using `forEach`)
	+ Cons:
		- Requires understanding of the `get()` method and its performance characteristics

**Library usage:**

There is no explicit library used in this benchmark. However, some JavaScript engines might optimize map access differently.

**Special JS feature or syntax:**

None mentioned.

**Alternative approaches:**

Other alternatives to compare the performance of accessing objects and maps could include:

* Using a more specific data structure, such as an array or Set
* Incorporating caching or memoization techniques
* Comparing performance with different iteration methods (e.g., `forEach`, `for...in`)
* Using a benchmarking library like Benchmark.js or jsperf

**Benchmark 2: Object access**

This individual test case measures the execution time for a single iteration of a loop that accesses each key in an object (`myObj`).

The benchmark definition is simple, with only one line of code:
```javascript
for (let i = 0; i < length; i++) {
    myObj.test;
}
```
This test case focuses on the overhead of accessing an object's properties.

Related benchmarks:

Access time Map vs Object (version: 0)

Comparing performance of: Object access vs Map access

Created: 2 years ago by: Guest

Jump to the latest result

Object access

Map access

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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