Benchmark: reduce 20000 v2 - MeasureThat.net

Script Preparation code:

var list = [];
var LIMIT = 10000;

Tests:

spread
for(var i = 0; i < LIMIT; i++) list = [...list, {a:2}];
concat
for(var i = 0; i < LIMIT; i++) list == list.concat([{a:2}]);
push
for(var i = 0; i < LIMIT; i++) list.push({a:2});
assign to index
for(var i = 0; i < LIMIT; i++) list[list.length] = {a:2};

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
concat
push
assign to index

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.87 Safari/537.36

Browser/OS: Chrome 80 on Linux

View result in a separate tab

Test name	Executions per second
spread	0.3 Ops/sec
concat	0.4 Ops/sec
push	477.5 Ops/sec
assign to index	209.6 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its different aspects.

**Benchmark Definition**

The provided benchmark definition is represented by two JSON files: one for the overall benchmark setup and another for individual test cases.

* The **Overall Benchmark Setup**: This section defines the basic properties of the benchmark, such as its name, description, script preparation code, and HTML preparation code. In this case, the script prepares an array `list` with a fixed length of 10,000 elements, each containing a single property `'a'` set to the value `2`.
* The **Individual Test Cases**: This section defines four test cases, each representing a different approach to appending or modifying the array. These approaches are:
	1. **`spread`**: Uses the spread operator (`[...list, {a:2}]`) to append a new element to the end of the array.
	2. **`concat`**: Uses the `concat()` method to concatenate an array with a single-element array containing the property `'a'`.
	3. **`push`**: Uses the `push()` method to add a new element at the end of the array.
	4. **`assign to index`**: Assigns the value `{a:2}` directly to the last index of the array.

**Comparison and Options**

The benchmark compares these four different approaches for appending or modifying the array. The pros and cons of each approach are:

* **Spread Operator (`[...list, {a:2}]`)**:
	+ Pros: Concise, efficient, and readable.
	+ Cons: May not work as expected in older browsers or environments that don't support the spread operator.
* **`concat()` Method**:
	+ Pros: Widespread support, easy to read, and well-documented.
	+ Cons: Can be slower than other approaches, especially for large arrays.
* **`push()` Method**:
	+ Pros: Fast, efficient, and widely supported.
	+ Cons: Less readable than other approaches, as the length of the array needs to be accessed explicitly.
* **Assigning to Index (`list[list.length] = {a:2}`)**:
	+ Pros: Fast, efficient, and concise.
	+ Cons: May not work as expected if the index is calculated dynamically or if the array length changes.

**Libraries and Special JS Features**

In this benchmark, none of the test cases explicitly use any libraries. However, it's worth noting that some of these approaches may rely on modern JavaScript features, such as:

* The spread operator (`[...list, {a:2}]`)
* Template literals (not directly used here but might be relevant for similar patterns)

**Other Alternatives**

There are other ways to append or modify an array in JavaScript. Some alternatives include:

* Using the `Array.prototype.push()` method with a callback function
* Using the `Array.prototype.unshift()` method to add elements at the beginning of the array
* Using the `Array.prototype.splice()` method to replace or insert elements

It's essential to consider factors such as performance, readability, and compatibility when choosing an approach for appending or modifying arrays in JavaScript.

Related benchmarks:

reduce 20000 v2 (version: 0)

Comparing performance of: spread vs concat vs push vs assign to index

Created: 4 years ago by: Guest

Jump to the latest result

spread

concat

push

assign to index

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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