Benchmark: Obj vs Map - MeasureThat.net

Script Preparation code:

var map = new Map();
var obj = {};

map.set('a', 5);
obj['a'] = 5;

var i = 0, count = 100000, 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:

No previous run results

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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 data and explain what's being tested, compared, and considered in the benchmark.

**Benchmark Overview**

The test compares the performance of two data structures: Maps (JavaScript objects with key-value pairs) and Objects (plain JavaScript objects). The primary focus is on looking up a value by its key.

**Script Preparation Code**

The script preparation code sets up both a Map (`map`) and an Object (`obj`). A key-value pair is added to each, with the same key `'a'` and value `5`. This ensures that both data structures have similar content when used in the tests.

**Html Preparation Code (None)**

Since there's no HTML preparation code provided, we'll focus on the JavaScript part of the benchmark.

**Benchmark Test Cases**

There are two test cases:

1. **Map lookup**: The test iterates `count` times (100,000) and for each iteration, it uses the `map.get()` method to retrieve the value associated with the key `'a'`.
2. **Obj lookup**: Similarly, this test iterates `count` times and uses the bracket notation (`obj['a']`) to access the same value.

**Library Usage**

In both tests, a JavaScript object is used as if it were a Map, relying on its built-in methods like `get()` for key-value lookups. There's no explicit library import or usage.

**Special JS Features/Syntax (None)**

This benchmark doesn't use any special JavaScript features or syntax beyond what's considered "normal" by the ECMAScript standard.

**Performance Considerations**

The performance comparison between Maps and Objects in this test hinges on their implementation details. Modern JavaScript engines, like V8 (used in Chrome), optimize these data structures for fast lookups using a combination of techniques:

* Cache- friendly layouts
* Fast hash table lookups
* Optimized access patterns

However, the difference might not be drastic due to the relatively small key-value pair size and the simple lookup pattern.

**Other Alternatives**

If you were to create alternative benchmarks, consider exploring other aspects of JavaScript performance, such as:

1. Array operations (e.g., indexing, slicing, searching)
2. Object methods (e.g., `forEach`, `filter`, `map`)
3. DOM manipulation
4. Event handling and queue management

When crafting an alternative benchmark, ensure it provides meaningful insights into specific use cases or aspects of JavaScript performance.

I hope this explanation helps you understand the test case being evaluated on MeasureThat.net!

Related benchmarks:

Obj vs Map (version: 0)

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

No previous run results

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