Benchmark: Adam -- Array concat vs spread operator vs push

Script Preparation code:

var jobs = [1, 1, 1];
var allJobs = [];

Tests:

Array.prototype.concat
for(i=0; i<100; i++){allJobs.concat(jobs);}
spread operator
for(i=0; i<100; i++){allJobs = [ ...jobs, ...allJobs ];}
directly push
for(i=0; i<100; i++){jobs.forEach(i => allJobs.push(i));}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator
directly push

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares three different approaches to concatenate an array in JavaScript:

1. `Array.prototype.concat()`
2. The new ES6 spread operator (`[ ...jobs, ...allJobs ]`)
3. Directly pushing elements onto the `allJobs` array using a `forEach` loop.

**Options Compared**

The benchmark is comparing two main options for concatenating arrays:

* Traditional `concat()` method
* New ES6 spread operator

Additionally, there's a third option being tested, which might seem less optimal at first glance: directly pushing elements onto the `allJobs` array using a `forEach` loop.

**Pros and Cons of Each Approach**

1. **Array.prototype.concat()**
	* Pros:
		+ Widely supported across browsers
		+ Well-documented and easy to understand
	* Cons:
		+ Can be slower than the spread operator due to its iterative nature
2. **ES6 Spread Operator ([ ...jobs, ...allJobs ] )**
	* Pros:
		+ Faster than `concat()` due to its ability to create a new array in one operation
		+ More concise and readable code
	* Cons:
		+ May not be supported by older browsers (though this is unlikely)
3. **Directly Pushing Elements onto the Array**
	* Pros:
		+ Can be optimized for specific use cases where `concat()` or spread operator are too expensive
	* Cons:
		+ Less readable and less efficient than the other two options

**Library Used**

In none of the benchmark test cases is a library used. The code is pure JavaScript, which means it can run on any device that supports JavaScript without relying on external dependencies.

**Special JS Features or Syntax**

The ES6 spread operator (`[ ...jobs, ...allJobs ]`) uses a new syntax introduced in ECMAScript 2018 (ES8). It's a feature that allows creating new arrays by spreading elements from existing arrays.

**Alternative Approaches**

Other approaches to concatenate arrays might include:

* `Array.prototype.push.apply()`: This method pushes all elements of an array onto the end of another array, which can be faster than concatenating individual elements.
* Custom looping: Using a traditional loop (e.g., `for` or `while`) to iterate over each element and push it onto the `allJobs` array.

Related benchmarks:

Adam -- Array concat vs spread operator vs push (version: 1)

Compare the new ES6 spread operator with the traditional concat() method and push

Comparing performance of: Array.prototype.concat vs spread operator vs directly push

Created: 4 years ago by: Registered User

Jump to the latest result

Array.prototype.concat

spread operator

directly push

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):