Benchmark: Object.fromEntries - 50 items

Script Preparation code:

var list = Array.from(Array(50), (x,i) => [i,i]);

Tests:

1
const obj = {}; for (const item of list) { obj[item[0]] = item[1]; }
2
const obj = Object.fromEntries(list);
3
const obj = list.reduce((result, item) => { result[item[0]] = item[1]; return result; }, {})
4
const obj = list.reduce((result, item) => ({ ...result, [item[0]]: item[1], }), {})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
1
2
3
4

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 Edg/127.0.0.0

Browser/OS: Chrome 127 on Windows

View result in a separate tab

Test name	Executions per second
1	1629382.5 Ops/sec
2	394486.9 Ops/sec
3	1578177.8 Ops/sec
4	238371.7 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a microbenchmark on JavaScript's `Object.fromEntries` method, which creates an object from a list of key-value pairs. The benchmark compares the performance of different approaches to achieve this goal.

**Approaches Compared**

There are four test cases:

1. **Manual Loop**: Using a manual loop to iterate over the list and assign values to the object.
2. **Object.fromEntries**: Using the built-in `Object.fromEntries` method to create an object from the list of key-value pairs.
3. **Reduce**: Using the `reduce` method on an array to accumulate key-value pairs into an object.
4. **Spread Operator**: Using the spread operator (`...`) with an initial value of `{}` and then adding key-value pairs using bracket notation.

**Pros and Cons of Each Approach**

1. **Manual Loop**:
	* Pros: Simple, straightforward approach.
	* Cons: May be slower due to the overhead of manual loop iteration.
2. **Object.fromEntries**:
	* Pros: Fastest approach, as it leverages the built-in method.
	* Cons: Requires JavaScript version 2019 or later (and some older browsers).
3. **Reduce**:
	* Pros: Efficient use of array methods to accumulate key-value pairs.
	* Cons: May be slower due to the overhead of `reduce` method invocation.
4. **Spread Operator**:
	* Pros: Simple, readable syntax using modern JavaScript features.
	* Cons: Requires JavaScript version 2018 or later (and some older browsers).

**Library and Special JS Features Used**

None are explicitly mentioned in the provided JSON.

**Other Considerations**

When choosing an approach, consider factors such as:

* Performance requirements
* Browser support (e.g., older browsers may not support `Object.fromEntries`)
* Code readability and maintainability
* JavaScript version limitations

**Alternatives to Object.fromEntries**

For older browsers or environments where `Object.fromEntries` is not supported, alternative approaches can be used. Some options include:

1. Using a library like Lodash (`_.fromPairs()`) or Moment.js (`moment.fromJS()`)
2. Implementing a custom loop-based approach using Array.prototype.map() and Object.assign()
3. Utilizing other object creation methods, such as `Object.keys()` and `forEach()`

Related benchmarks:

Object.fromEntries - 50 items (version: 0)

Comparing performance of: 1 vs 2 vs 3 vs 4

Created: one year ago by: Guest

Jump to the latest result

1

2

3

4

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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