Benchmark: for loop: object vs map

Script Preparation code:

var mapData = [];
for (let i = 0; i < 10000; i++) {
  mapData.push([i, `object${i}`]);
}
var map = new Map(mapData);
                          
var obj = {};
for (let i = 0; i < 10000; i++) {
  obj[i] = `object${i}`;
}

Tests:

for loop of Map
let sum = 0; for (let [key, val] of map) { sum += key; }
for loop of Object
let sum = 0; for (let [key, val] of Object.entries(obj)) { sum += key; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop of Map
for loop of Object

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.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark test case, specifically comparing the performance of iterating over an object using two approaches: `Map` and `Object`. The benchmark tests how fast each approach can iterate over 10,000 objects in a array-like structure.

**Options compared**

Two options are being compared:

1. **For loop of Map**: This option uses the `Map` data structure to store the objects, and then iterates over it using a for loop. The `Map` data structure is designed to provide fast lookup, insertion, and deletion operations.
2. **For loop of Object**: This option uses an object (created using `{}`) to store the objects, and then iterates over it using a for loop. Objects in JavaScript are used to store key-value pairs.

**Pros and Cons**

* **Map**:
	+ Pros: Fast lookup and iteration operations, as `Map` is optimized for these use cases.
	+ Cons: Requires more memory, as each object needs to be stored in the `Map`.
* **Object**:
	+ Pros: More memory-efficient, as objects only store key-value pairs without any extra overhead.
	+ Cons: Slower lookup and iteration operations compared to `Map`.

**Other considerations**

When choosing between these two approaches, consider the trade-off between memory usage and performance. If memory efficiency is a concern, using an object might be a better choice. However, if faster iteration and lookup are essential, using a `Map` might be a better option.

**Library used**

No specific library is mentioned in the provided JSON, but both `Map` and `Object` are built-in JavaScript data structures.

**Special JS feature or syntax**

The benchmark uses modern JavaScript syntax, including:

* **Template literals**: Used to create string literals with expressions inside them (e.g., `object${i}`).
* **Arrow functions**: Not explicitly used in this benchmark, but might be useful for creating smaller function bodies.
* **Spread syntax**: Not explicitly used in this benchmark, but might be helpful for creating larger data structures.

**Alternatives**

Other alternatives to compare performance include:

1. Using an array with `forEach` or a traditional for loop.
2. Using a `Set` instead of an object (for faster lookup operations).
3. Using a library like Lodash or Ramda, which provide optimized iteration and lookup functions.
4. Using a different programming paradigm, such as using iterators or generators.

Please note that the choice of alternative depends on the specific requirements and constraints of the project.

Related benchmarks:

for loop: object vs map (version: 0)

Comparing performance of: for loop of Map vs for loop of Object

Created: 3 years ago by: Guest

Jump to the latest result

for loop of Map

for loop of Object

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):