Benchmark: Map vs Object 10 iterations

Script Preparation code:

var map = new Map();
var obj = {};

map.set('a', 5);
obj['a'] = 5;

var i = 0, count = 10, a;

Tests:

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

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: 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

Browser/OS: Chrome 142 on Windows

View result in a separate tab

Test name	Executions per second
Map lookup	1070717.1 Ops/sec
Obj lookup	1103828.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested, compared, and the pros and cons of each approach.

**Benchmark Definition:**
The benchmark definition represents a JavaScript microbenchmark that compares the performance of two data structures: Maps (in this case, using the `Map` class from the JavaScript standard library) and Objects (in this case, using plain JavaScript objects).

**Script Preparation Code:**
The script preparation code initializes two variables:
- `map`: an empty Map object.
- `obj`: an empty Object literal.

It then sets a key-value pair on both `map` and `obj`, with the key `'a'` mapped to the value `5`.

**Html Preparation Code:**
The html preparation code is null, which means that no HTML template or markup is provided for this benchmark. This suggests that the focus is solely on measuring the performance of the JavaScript code.

**Individual Test Cases:**
There are two test cases:

1. **Map lookup**: The first test case uses a `for` loop to iterate 10 times, and in each iteration, it retrieves the value associated with the key `'a'` from the `map` object using the `get()` method.
2. **Object lookup**: The second test case is similar to the first one, but instead of using the `Map` class, it uses plain JavaScript objects (`obj`) and accesses the value associated with the key `'a'` using bracket notation (`obj['a']`).

**Pros and Cons of each approach:**

- **Maps**:
  - Pros:
    * Maps provide a more convenient way to store key-value pairs, especially when dealing with large datasets.
    - They offer better performance compared to objects for iteration, as they don't require the browser's DOM tree to be traversed.
  - Cons:
    * Maps are not supported in older browsers or environments that don't have access to modern JavaScript features.
    * Some developers might find them less intuitive than using plain objects.

- **Objects** (plain JavaScript objects):
  - Pros:
    * Objects are supported across a wide range of browsers and environments, making them suitable for cross-browser testing.
    - They can be easily modified and extended to fit specific use cases.
  - Cons:
    - Accessing properties in an object using bracket notation (`obj['a']`) might be slightly slower than using the `Map` class's `get()` method.

**Library:**
The library being used is not explicitly mentioned, but based on the code, it appears to be a JavaScript implementation of Maps and Objects. If you're interested in exploring alternative libraries, some popular ones include:

- Lodash (specifically, its `mapValues` function)
- jQuery (with its `.map()` method)

**Special JS Features or Syntax:**
There are no special features or syntaxes being tested in this benchmark, as it's focused solely on comparing the performance of two data structures using simple loops.

**Other Alternatives:**
If you're interested in exploring other alternatives for microbenchmarking JavaScript performance, consider:

- The `microbench` library, which provides a set of built-in benchmarks and utilities for measuring JavaScript performance.
- The `jsperf` library (now deprecated), which offered a similar range of features to `microbench`.
- Browser-specific benchmarking tools, such as Chrome DevTools' Performance panel or Firefox's Performance tab.

Related benchmarks:

Map vs Object 10 iterations (version: 0)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup

Created: 2 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):