Benchmark: fromEntries vs reduce fight!

Script Preparation code:

var data = [...Array(10000)].map((_, i) => [i, i]);

Tests:

FromEntries
Object.fromEntries(data);
Reduce
data.reduce((acc, [k, v]) => { acc[k] = v; return acc; }, {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
FromEntries
Reduce

Fastest: N/A

Slowest: N/A

Latest 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 dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided JSON benchmark measures the performance of two approaches to convert an array of key-value pairs into an object: `Object.fromEntries()` and the `reduce()` method.

**Options compared:**

1. **`Object.fromEntries()`**: This method creates a new object from an iterable (in this case, an array) of key-value pairs.
2. **`reduce()`**: This method applies a function to each element in an array, accumulating a result. In this benchmark, the `reduce()` method is used to convert the array into an object.

**Pros and Cons:**

*   **`Object.fromEntries()`**:
    *   Pros:
        *   More concise and readable code.
        *   Fewer lines of code compared to implementing `reduce()`.
        *   Less prone to errors due to its built-in implementation.
    *   Cons:
        *   Performance might be slower since it's a newer method with less optimization.
*   **`reduce()`**:
    *   Pros:
        *   More control over the conversion process, allowing for custom logic.
        *   Can be more efficient in certain scenarios due to its native implementation.
    *   Cons:
        *   More verbose code compared to `Object.fromEntries()`.
        *   Requires understanding of how to implement and use it correctly.

**Library/Function usage:**

In this benchmark, the `reduce()` method is used from the built-in JavaScript library.

**Special JS feature/syntax:**

None mentioned in the provided information. If any special features or syntax were being tested, they would be explained here.

**Other alternatives:**

Before relying on either of these methods, consider the following alternative approaches:

*   **Manual object creation**: You can manually create an object by looping through the array and assigning values to the corresponding keys.
    ```javascript
const obj = {};
data.forEach(([k, v]) => {
  obj[k] = v;
});
```
*   **Using `Array.prototype.map()` and `Object.fromEntries()` combination**: Although not as efficient as using `reduce()`, you can create an object from an array by mapping each element to a key-value pair.
    ```javascript
const obj = Object.fromEntries(data.map(([k, v]) => [k, v]));
```
*   **Using a library like Lodash** (not mentioned in the provided information): Depending on your needs and performance requirements, you might consider using a utility library like Lodash to handle object creation.

In conclusion, when working with arrays of key-value pairs, choosing between `Object.fromEntries()` and `reduce()` depends on your specific use case. If readability is crucial and performance isn't an issue, `Object.fromEntries()` is the better choice. Otherwise, using `reduce()` provides more control and potentially better performance. Always consider alternative approaches for further optimization or to suit your project's unique needs.

Related benchmarks:

fromEntries vs reduce fight! (version: 0)

Comparing performance of: FromEntries vs Reduce

Created: 2 years ago by: Guest

Jump to the latest result

FromEntries

Reduce

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):