Benchmark: Object.fromEntries vs reduce without toString

Script Preparation code:

var data = { ...Array.from(Array(10000).keys()) };

Tests:

Object.fromEntries
Object.fromEntries(Object.entries(data).map((key, value) => [key, value]));
Reduce (reuse object)
Object.entries(data).reduce((acc, [k, v]) => { acc[k] = v; return acc; }, {});
Reduce (creating temporary objects)
Object.entries(data).reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.fromEntries
Reduce (reuse object)
Reduce (creating temporary objects)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
Object.fromEntries	86.4 Ops/sec
Reduce (reuse object)	734.7 Ops/sec
Reduce (creating temporary objects)	29.7 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is tested, the options compared, pros and cons of each approach, and other considerations.

**Benchmark Overview**

The benchmark measures the performance difference between three approaches for creating an object from an array of key-value pairs:

1. `Object.fromEntries`
2. `Array.prototype.reduce()` with a custom callback function that creates a new object
3. `Array.prototype.reduce()` with a custom callback function that directly assigns values to the accumulator object

**Script Preparation Code**

The script preparation code creates an object `data` containing 10,000 key-value pairs using `Array.from(Array(10000).keys())`.

**Benchmark Definition JSON**

The benchmark definition json provides three test cases:

1. `Object.fromEntries`: uses `Object.fromEntries()` to create the object from the array of key-value pairs.
2. `Reduce (reuse object)`: uses `Array.prototype.reduce()` with a custom callback function that creates a new object, reusing the accumulator (`acc`) for each iteration.
3. `Reduce (creating temporary objects)`: uses `Array.prototype.reduce()` with a custom callback function that directly assigns values to the accumulator object, creating a new object in each iteration.

**Library Used**

In this benchmark, the `Object.fromEntries()` method is used from the ECMAScript standard library.

**Special JS Feature/Syntax**

None mentioned explicitly. However, it's worth noting that the use of arrow functions (e.g., `(key, value) => [key, value]`) in the benchmark definition json demonstrates a modern JavaScript feature.

**Options Compared**

The three test cases compare different approaches to creating an object from an array of key-value pairs:

1. `Object.fromEntries()`: uses a built-in method that is designed for this specific use case.
2. `Reduce (reuse object)`: uses the `Array.prototype.reduce()` method with a custom callback function, reusing the accumulator object for each iteration.
3. `Reduce (creating temporary objects)`: uses the same `Array.prototype.reduce()` method as above, but with a different implementation that creates a new object in each iteration.

**Pros and Cons of Each Approach**

1. **`Object.fromEntries()`**:
	* Pros: efficient, concise, and easy to read.
	* Cons: may not be supported in older browsers or environments.
2. **`Reduce (reuse object)`**:
	* Pros: can take advantage of browser optimizations for reduce operations.
	* Cons: requires manual management of the accumulator object, which can lead to code complexity.
3. **`Reduce (creating temporary objects)`**:
	* Pros: simple and easy to understand.
	* Cons: creates a new object in each iteration, which can be inefficient.

**Other Considerations**

When choosing between these approaches, consider the following factors:

* Performance: `Object.fromEntries()` is likely to be the fastest option due to its optimized implementation.
* Code complexity: If you need to manage an accumulator object manually, `Reduce (reuse object)` might be a better choice. However, this approach can lead to code complexity and maintenance issues.
* Browser support: If you need to support older browsers, consider using a fallback approach or modifying the benchmark to use a different method.

**Alternatives**

If you don't have access to modern JavaScript features like `Object.fromEntries()`, you can explore other alternatives:

1. Use `Array.prototype.reduce()` with a custom callback function that creates a new object in each iteration.
2. Implement your own function for creating an object from an array of key-value pairs.

However, keep in mind that these alternatives may not offer the same level of performance or conciseness as the original benchmark.

Related benchmarks:

Object.fromEntries vs reduce without toString (version: 0)

Comparing performance of: Object.fromEntries vs Reduce (reuse object) vs Reduce (creating temporary objects)

Created: 3 years ago by: Guest

Jump to the latest result

Object.fromEntries

Reduce (reuse object)

Reduce (creating temporary objects)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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