Benchmark: concat vs push - MeasureThat.net

Script Preparation code:

var someBigArray = [];
var anotherArray = [];

for (var i = 0; i < 1000; i++) {
  someBigArray.push(10);
  anotherArray.push(10);
}

Tests:

concat
var thing = someBigArray.concat(anotherArray);
push
var thing = [] someBigArray.forEach(function(item) { thing.push(anotherArray); }); anotherArray.forEach(function(item) { thing.push(anotherArray); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
push

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**What's being tested?**

The benchmark is comparing two approaches to concatenate arrays: `concat` and `push`. The test case uses two arrays, `someBigArray` and `anotherArray`, which are initialized with 1000 elements each. The script preparation code creates these arrays and populates them with values.

**Options compared**

There are two options being compared:

1. **Concatenation using the `concat` method**: This approach involves calling the `concat` method on one of the arrays, passing the other array as an argument. For example: `var thing = someBigArray.concat(anotherArray);`
2. **Concatenation using the `push` method with a callback**: This approach involves iterating over one of the arrays and pushing the values from another array onto it using the `push` method. For example: `someBigArray.forEach(function(item) { thing.push(anotherArray); });`

**Pros and cons of each approach**

1. **Concatenation using `concat`**
	* Pros:
		+ More explicit and readable code
		+ Less prone to errors due to the guaranteed behavior of the `concat` method
	* Cons:
		+ Creates a new array, which can be memory-intensive for large arrays
2. **Concatenation using `push` with a callback**
	* Pros:
		+ More efficient in terms of memory usage (no need to create a new array)
	* Cons:
		+ Less explicit and readable code
		+ Can lead to errors if the callback function is not implemented correctly

**Library used**

There is no library explicitly mentioned in the benchmark. However, it's worth noting that the `concat` method uses the JavaScript Array.prototype.concat() method, which is a built-in method.

**Special JS feature or syntax**

The benchmark uses the `forEach` method on arrays, which is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). If the test was run with an older version of JavaScript that didn't support `forEach`, it would likely throw an error.

**Other alternatives**

In addition to the `concat` and `push` approaches mentioned in the benchmark, there are other ways to concatenate arrays:

1. **Using the spread operator (`...`)**: This method involves using the spread operator to merge two arrays: `var thing = [...someBigArray, ...anotherArray];`
2. **Using a loop**: This approach involves iterating over both arrays and pushing values onto an accumulator array.

It's worth noting that these alternative approaches may have different performance characteristics and trade-offs compared to the `concat` and `push` methods used in the benchmark.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Windows

View result in a separate tab

Test name	Executions per second
concat	641651.4 Ops/sec
push	4181.9 Ops/sec

Related benchmarks:

concat vs push (version: 0)

Comparing performance of: concat vs push

Created: 8 years ago by: Guest

Jump to the latest result

concat

push

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):