Benchmark: Object.fromEntries vs Map

Script Preparation code:

var data = Object.entries({ ...Array.from(Array(10000).keys()) }).map((key, value) => [key, value]);

Tests:

Object.fromEntries
Object.fromEntries(data);
Map
new Map(data)

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Map

3K/s

Object.fromEntries

330/s

Fastest: Map (8.3x faster)

View exact numbers

✓ Map: 2,736 ops/sec
• Object.fromEntries: 330 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.fromEntries
Map

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:145.0) Gecko/20100101 Firefox/145.0

Browser/OS: Firefox 145 on Mac OS X 10.15

View result in a separate tab

Map

2K/s

Object.fromEntries

426/s

View exact numbers

Test name	Executions per second
✓ Map	1,832 Ops/sec
Object.fromEntries	426 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark that compares the performance of two data structures: `Object.fromEntries` and `Map`. The benchmark is designed to measure which approach is faster for creating an object from an array of key-value pairs.

**Script Preparation Code**

The script preparation code creates a dataset by:

1. Generating an array of 10,000 keys using `Array.from(Array(10000).keys())`.
2. Creating an array of equivalent key-value pairs using `Object.entries`.

The resulting data is then passed to both the `Object.fromEntries` and `Map` methods.

**Options Compared**

Two options are compared in this benchmark:

1. **Object.fromEntries**: This method creates a new object by taking an iterable of key-value pairs as an argument.
2. **Map**: A built-in JavaScript data structure that stores key-value pairs in an ordered collection.

**Pros and Cons of Each Approach**

* **Object.fromEntries**:
	+ Pros:
		- More intuitive for creating objects with named properties (e.g., `const obj = Object.fromEntries([...])`).
		- Can be more readable for simple cases.
	+ Cons:
		- May have slower performance due to the overhead of object creation and property access.
* **Map**:
	+ Pros:
		- Often faster than `Object.fromEntries` because it avoids the overhead of object creation and property access.
		- More efficient for large datasets or when working with multiple key-value pairs.
	+ Cons:
		- Less intuitive for creating objects with named properties (e.g., `const obj = new Map([...])`).

**Library/Function Used**

None, as both methods are built into JavaScript.

**Special JS Feature/Syntax**

No special features or syntax are used in this benchmark. However, if you're interested in exploring other performance comparisons, MeasureThat.net also tests various other JavaScript methods and libraries.

**Other Alternatives**

If you're looking for alternatives to `Object.fromEntries` and `Map`, consider the following:

* For creating objects:
	+ `JSON.parse(JSON.stringify(data))`: A simple way to create an object from a JSON-like data structure.
	+ `Array.prototype.reduce()`: Can be used to create an object by reducing an array of key-value pairs.
* For working with key-value pairs:
	+ `Array.prototype.forEach()`: Can be used to iterate over key-value pairs in an array.
	+ `Set` or `Map` alternatives, such as `Array.prototype.reduce()` or third-party libraries like Lodash.

Keep in mind that the choice of method depends on your specific use case and requirements.

Object.fromEntries vs Map (version: 0)

Comparing performance of: `Object.fromEntries vs Map`

Created: one year ago by: Registered User

Go to the latest result

Object.fromEntries

Map

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Object.fromEntries vs Map (version: 0)

Comparing performance of: Object.fromEntries vs Map

Created: one year ago by: Registered User

Go to the latest result

Object.fromEntries

Map

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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Comparing performance of: `Object.fromEntries vs Map`