Benchmark: push vs concat - MeasureThat.net

Script Preparation code:

function getArray() {
  var arr = new Array(1000);
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }
  return arr;
}

var arr = getArray();
var toAdd = getArray();

Tests:

.push()
for (var i = 0, iM = toAdd.length; i < iM; i++) { arr.push(toAdd[i]); }
.concat()
arr = arr.concat(toAdd);
.push() w/ .apply()
Array.prototype.push.apply(arr, toAdd);
push apply alt
arr.push.apply(arr, toAdd);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.push()
.concat()
.push() w/ .apply()
push apply alt

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case created on MeasureThat.net. The test compares the performance of three different approaches to add elements to an array:

1. `.push()`: Using the `Array.prototype.push()` method.
2. `.concat()`: Using the `Array.prototype.concat()` method.
3. `.push() w/ .apply()` and `.push apply alt`: Using the `Array.prototype.push.apply()` method.

**Benchmark Script**

The script preparation code is identical for all test cases:
```javascript
function getArray() {
  var arr = new Array(1000);
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }
  return arr;
}

var arr = getArray();
var toAdd = getArray();
```
This script creates an array `arr` of length 1000, fills it with numbers from 0 to 999, and then assigns another identical array `toAdd` to the same variable.

**Benchmark Test Cases**

There are four test cases:

1. `.push()`: This test case uses the original approach: adding elements to the `arr` array using `Array.prototype.push()`.
2. `.concat()`: This test case uses the `Array.prototype.concat()` method to concatenate the `toAdd` array with the existing `arr` array.
3. `.push() w/ .apply()`: This test case uses the `Array.prototype.push.apply()` method to add elements from the `toAdd` array to the `arr` array using the spread operator (`...`) is not used, but rather the apply method.
4. `.push apply alt`: This test case uses an alternative implementation of `push.apply()`, which is not explicitly shown in the JSON.

**Library and Special Features**

The provided script does not use any external libraries or special JavaScript features beyond the standard library functions mentioned above (Array.prototype.push(), Array.prototype.concat(), etc.).

**Pros and Cons of Different Approaches**

Here's a brief summary of the pros and cons of each approach:

1. `.push()`: This is the most straightforward approach, as it's native to the language. However, it may incur additional overhead due to the need to iterate over the entire array.
2. `.concat()`: This method concatenates two arrays in a single operation, which can be more efficient than pushing individual elements. However, it creates a new array and may consume more memory.
3. `.push() w/ .apply()`:
	* Pros: This approach uses the `Array.prototype.push.apply()` method, which can be more efficient than the native `Array.prototype.push()` method for large arrays.
	* Cons: The use of `Array.prototype.push.apply()` requires a bit more setup and may not be as intuitive as the native `push()` method.

**Other Alternatives**

There are other approaches to add elements to an array, such as:

1. Using the spread operator (`...`): This can be used in newer JavaScript versions (ECMAScript 2018+) to create a new array by copying elements from another array.
2. Using `Array.prototype.reduce()` or `Array.prototype.forEach()`: These methods can be used to add elements to an array, but they may have different performance characteristics and are less common than the native `push()` method.

Keep in mind that these alternatives may not be as straightforward or well-supported as the standard library functions mentioned above.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/11.1 Safari/605.1.15

Browser/OS: Safari 11 on Mac OS X 10.13.4

View result in a separate tab

Test name	Executions per second
.push()	4833.4 Ops/sec
.concat()	4.3 Ops/sec
.push() w/ .apply()	36995.5 Ops/sec
push apply alt	1807.8 Ops/sec

Related benchmarks:

push vs concat (version: 0)

Comparing performance of: .push() vs .concat() vs .push() w/ .apply() vs push apply alt

Created: 7 years ago by: Guest

Jump to the latest result

.push()

.concat()

.push() w/ .apply()

push apply alt

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):