Benchmark: object create - MeasureThat.net

Tests:

object.assign
var obj1 = {foo: 'bar', that: 1, type: true}; var obj2 = Object.assign({}, obj1, {type: false});
keys
var obj1 = {foo: 'bar', that: 1, type: true}; var obj2 = Object.keys(obj1).map(key => obj1[key]); obj2.type = false;
for in
var obj1 = {foo: 'bar', that: 1, type: true}; var obj2 = {}; for(var key in obj1) { if(!obj1.hasOwnProperty(key)) { return; } obj2[key] = obj1[key]; } obj2.type = false;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
object.assign
keys
for in

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its results.

**Benchmark Overview**

The benchmark tests three different approaches to create an object in JavaScript:

1. Using `Object.assign()`
2. Using `Array.prototype.keys()` (also known as "keys" in the benchmark)
3. Using a traditional `for...in` loop

These approaches are compared to measure their performance differences.

**Options Compared**

The options being compared are:

* **Object.assign()**: A built-in method that creates a new object by copying properties from an existing object.
* **Array.prototype.keys()**: A method that returns an array of property names of the given object. The "keys" approach uses this method to create a new object by mapping over the property names.
* **Traditional `for...in` loop**: This is a basic approach that iterates over the properties of an object using a traditional loop.

**Pros and Cons**

Here are some pros and cons for each approach:

* **Object.assign()**:
	+ Pros: Concise, efficient, and widely supported.
	+ Cons: May not work as expected if the source object has a non-standard property name or if it's not an object (e.g., a string).
* **Array.prototype.keys()**:
	+ Pros: Modern, concise, and easy to read. It avoids issues with non-standard property names.
	+ Cons: May be slower than `Object.assign()` due to the overhead of creating an array of property names.
* **Traditional `for...in` loop**:
	+ Pros: Well-established, easy to understand, and works in older browsers.
	+ Cons: More verbose, may have performance issues due to the loop.

**Library Usage**

There is no explicit library usage mentioned in the benchmark definition or test cases. However, the use of `Array.prototype.keys()` implies a modern JavaScript feature that was introduced with ECMAScript 2015 (ES6).

**Special JS Feature/Syntax**

The "keys" approach uses the `Array.prototype.keys()` method, which is a modern JavaScript feature introduced in ES6. This method returns an array-like object containing the property names of the given object.

**Alternatives**

Other alternatives for creating objects in JavaScript include:

* Using object literal notation (e.g., `{ foo: 'bar', that: 1 }`)
* Using the `Object.create()` method
* Using a constructor function to create objects

These alternatives may have different performance characteristics or trade-offs, but they are not explicitly compared in this benchmark.

Related benchmarks:

object create (version: 0)

Comparing performance of: object.assign vs keys vs for in

Created: 8 years ago by: Guest

Jump to the latest result

object.assign

keys

for in

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):