Benchmark: assign comparison

Script Preparation code:

var arr = [];
var result = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = Math.random();
}

Tests:

spread
for (var i = 0, len = arr.length; i < len; i++) { const firstObject = { sampleData: 'Hello world', sampleData1: 'Hello world', sampleData2: 'Hello world', sampleData3: 'Hello world' }; result.push({...firstObject, isCloseTag: true}); }
assign
for (var i = 0, len = arr.length; i < len; i++) { const firstObject = { sampleData: 'Hello world', sampleData1: 'Hello world', sampleData2: 'Hello world', sampleData3: 'Hello world' }; result.push(Object.assign({firstObject, isCloseTag: true})); }
spread new
for (var i = 0, len = arr.length; i < len; i++) { const firstObject = { sampleData: 'Hello world', sampleData1: 'Hello world', sampleData2: 'Hello world', sampleData3: 'Hello world' }; const newObject = {...firstObject}; newObject.isCloseTag = true; result.push(newObject); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
assign
spread new

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 break down the provided JSON and explain what is tested, compared, and their pros and cons.

**Benchmark Definition**
The benchmark definition is a set of three test cases that compare different approaches to assign or spread properties to an object in JavaScript.

1. **Assign**: This approach uses the `Object.assign()` method to create a new object with the original object's properties and additional ones.
2. **Spread (New Object)**: This approach uses the spread operator (`...`) to create a new object with the original object's properties and additional ones.
3. **Assign vs Spread**: The third option is not explicitly defined, but it seems to be an alternative to the previous two approaches.

**Options Comparison**

* **Object.assign()**:
	+ Pros: It is a widely supported method in older browsers and can handle cases where the target object has existing properties with the same name.
	+ Cons: It can lead to unexpected behavior if the original object's properties have names that collide with the additional ones.
* **Spread Operator (`...`)**:
	+ Pros: It is a modern and efficient way to create new objects, and it avoids collisions by using dot notation for property names.
	+ Cons: It may not be supported in older browsers or environments.

**Other Considerations**

* In all cases, the test creates an array of 1000 objects with random properties and assigns/ spreads them to a result array. This allows for a fair comparison of the performance and efficiency of each approach.
* The `isCloseTag` property is added to the original object to introduce some variability in the testing.

**Library Usage**
There are no libraries explicitly mentioned in the benchmark definition, but it uses a few built-in JavaScript features:

* **Object.assign()**: Part of the ECMAScript standard since ECMAScript 5 (2011)
* **Spread Operator (`...`)**: Part of the ECMAScript standard since ECMAScript 2018 (2017)

**Special JS Feature/Syntax**
The spread operator (`...`) is a relatively recent addition to JavaScript, introduced in ECMAScript 2015 (ES6). It allows for more concise and expressive way to create new objects.

Other alternatives that could be considered are:

* Using `JSON.parse(JSON.stringify(obj))` to clone an object
* Using a library like Lodash's `cloneDeep()` function to clone an object
* Using a custom implementation of the assignment operator (`=`) or spread operator (`...`)

However, these alternatives may not provide the same level of performance and efficiency as the built-in `Object.assign()` method or spread operator (`...`).

Related benchmarks:

assign comparison (version: 1)

Comparing performance of: spread vs assign vs spread new

Created: 5 years ago by: Registered User

Jump to the latest result

spread

assign

spread new

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):