Benchmark: for loop: object vs map v2

Script Preparation code:

var mapData = [];
for (let i = 0; i < 100000; i++) {
  mapData.push([i, `object${i}`]);
}
var map = new Map(mapData);
                          
var obj = {};
for (let i = 0; i < 100000; 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:

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

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**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The benchmark compares two approaches for iterating over objects: using a `Map` data structure and using the `Object.entries()` method.

**Options Compared**

The options being compared are:

1. **`for...of` loop with `Map`**: This approach uses the `for...of` loop to iterate over the key-value pairs of a `Map`. The `mapData` array is first converted to a `Map`, and then the `for...of` loop is used to iterate over its entries.
2. **`for...in` loop with `Object.entries()`**: This approach uses the `for...in` loop in combination with the `Object.entries()` method to iterate over the key-value pairs of an object.

**Pros and Cons**

### For...of Loop with Map

Pros:

* Can be more concise and expressive than traditional `for...in` loops.
* Provides a clear and efficient way to iterate over key-value pairs of a map.

Cons:

* May not work as expected if the keys are not numeric (e.g., using a string or symbol).
* Requires support for ECMAScript 2015+ syntax.

### For...in Loop with Object.entries()

Pros:

* Works even when the object has non-numeric keys.
* Can be used in older browsers that don't support `for...of` loops.
* More portable across different browsers and environments.

Cons:

* Requires more code to achieve the same result, as it involves calling an additional method (`Object.entries()`).
* May be less concise than using a `for...of` loop with a map.

**Other Considerations**

When choosing between these two approaches, consider the following factors:

* **Performance**: For large datasets or performance-critical code, the `for...of` loop with a map may offer better performance due to its efficiency in iterating over key-value pairs.
* **Readability and Conciseness**: If readability and conciseness are important, using a `for...of` loop with a map might be a better choice. However, if you need to support older browsers or want more control over the iteration process, the `for...in` loop with `Object.entries()` might be a better fit.

**Library Usage**

In this benchmark, the `Map` data structure and its associated methods (`entries()`) are used as part of the test case. The `Map` library is built-in to JavaScript and does not require any external imports.

There are no libraries explicitly mentioned in the benchmark definition or test cases. However, if you were to extend this benchmark to compare other iteration methods (e.g., using a `Set`, an array, or a custom iterator), you would need to consider additional factors, such as performance overhead and compatibility with different browsers and environments.

**Special JS Features/Syntax**

This benchmark does not explicitly use any special JavaScript features or syntax. It relies on standard ECMAScript syntax for iteration and data structures.

Related benchmarks:

for loop: object vs map v2 (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):