Benchmark: forEach concat vs reduce push vs forEach push vs reduce concat performance test 2

Tests:

forEach concat
var a = [{nested: [ "hello", true, 7 ]}, {nested: [ 1, 2 ]}]; let b = []; a.forEach((item) => { b = b.concat(item.nested); });
Reduce push
var a = [{nested: [ "hello", true, 7 ]}, {nested: [ 1, 2 ]}]; const b = a.reduce((acc, item) => { acc.push(...item.nested); return acc }, []);
Reduce concat
var a = [{nested: [ "hello", true, 7 ]}, {nested: [ 1, 2 ]}]; const b = a.reduce((acc, item) => { return acc.concat(item.nested); }, []);
forEach push
var a = [{nested: [ "hello", true, 7 ]}, {nested: [ 1, 2 ]}]; let b = []; a.forEach((item) => { b.push(...item.nested); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach concat
Reduce push
Reduce concat
forEach push

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
forEach concat	6340000.5 Ops/sec
Reduce push	15055504.0 Ops/sec
Reduce concat	6816718.0 Ops/sec
forEach push	13623023.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The provided benchmark tests four different approaches to concatenate arrays in a nested object:

1. `forEach concat`
2. `Reduce push`
3. `Reduce concat`
4. `forEach push`

Each test case involves an array `a` containing two objects with a nested array. The goal is to create a new array `b` by concatenating the nested arrays from each object.

**Library and Syntax**

The benchmark uses the following library:

* None, as no specific library is mentioned in the provided code snippets.

There are no special JS features or syntax used beyond standard JavaScript syntax.

**Approach Options**

Let's break down each approach and their pros and cons:

### 1. `forEach concat`

```javascript
a.forEach((item) => {
  b = b.concat(item.nested);
});
```

Pros:

* Simple and straightforward implementation.
* Easy to understand for beginners.

Cons:

* Can be slower due to the creation of a new array on each iteration.

### 2. `Reduce push` (with `reduce()` function)

```javascript
const b = a.reduce((acc, item) => {
  acc.push(...item.nested);
  return acc;
}, []);
```

Pros:

* More efficient than `forEach concat`, as it uses a single array creation operation.
* Can be faster for large datasets.

Cons:

* May require additional setup and understanding of the `reduce()` function.

### 3. `Reduce concat` (with `concat()` method)

```javascript
const b = a.reduce((acc, item) => {
  return acc.concat(item.nested);
}, []);
```

Pros:

* Similar to `Reduce push`, but uses the `concat()` method instead of `push()`.
* May be slightly faster than `Reduce push`.

Cons:

* Requires additional method calls, which can add overhead.

### 4. `forEach push` (with `push()` function)

```javascript
let b = [];
a.forEach((item) => {
  b.push(...item.nested);
});
```

Pros:

* Easy to understand and implement.
* Similar performance to `Reduce push`.

Cons:

* Can be slower than `Reduce push` due to the creation of a new array on each iteration.

**Benchmark Results**

The provided benchmark results show the execution per second for each test case. The top performer is `Reduce push`, followed closely by `forEach push`. This suggests that using the `reduce()` function and pushing elements onto an accumulator array can be an efficient way to concatenate arrays in a nested object.

Keep in mind that these results may vary depending on the specific use case, dataset size, and JavaScript engine used.

Related benchmarks:

forEach concat vs reduce push vs forEach push vs reduce concat performance test 2 (version: 0)

Comparing performance of: forEach concat vs Reduce push vs Reduce concat vs forEach push

Created: 3 years ago by: Guest

Jump to the latest result

forEach concat

Reduce push

Reduce concat

forEach push

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):