Benchmark: Creating new property, 1

Script Preparation code:

data = [];

for (let i = 0; i < 1000000; i++) {
  data[i] = {
    prop: '1'
  };
}

Tests:

For
for (let i = 0; i < data.length; i++) { data[i].newProp = '1'; }
Map
data.map((current) => { current.newProp = '1'; });
Reduce
data.reduce((accumulator, current) => { accumulator.push({ ...current, newProp: '1' }); return accumulator; }, []);
Foreach
data.forEach((current) => { current.newProp = '1'; });
For reversed
for (let i = data.length - 1; i >= 0; i--) { data[i].newProp = '1'; }
while
let i = 0; while (i !== data.length) { data[i].newProp = '1'; i++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For
Map
Reduce
Foreach
For reversed
while

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The provided JSON represents a benchmark for creating a new property on an array element in JavaScript. The script preparation code creates an array `data` with 1 million elements, each initialized with a single property `prop` set to `'1'`. The goal is to measure the performance of different approaches to add a new property (`newProp`) to these elements.

**Options Compared**

The benchmark compares six different approaches:

1. **For loop**: A traditional for loop iterates over the array elements and assigns the value to each element's `newProp` property.
2. **Map**: The `map()` method applies a function to each element in the array, returning a new array with the modified elements.
3. **Reduce**: The `reduce()` method accumulates the modifications from each element in the array, pushing them onto an accumulator array.
4. **Foreach loop**: A for-each loop iterates over the array elements and assigns the value to each element's `newProp` property, similar to a traditional for loop but with more concise syntax.
5. **For loop (reversed)**: A for loop that iterates over the array elements in reverse order, starting from the last element and moving backwards to the first.
6. **While loop**: A while loop iterates until it reaches the end of the array, incrementing an index variable `i` and assigning the value to each element's `newProp` property.

**Pros and Cons**

Each approach has its advantages and disadvantages:

* **For loops (traditional and foreach)**: Simple, straightforward, and easy to understand. May be slower due to the overhead of explicit loop control.
* **Map**: Modern, concise, and efficient. Returns a new array with modified elements, which can be beneficial if you need to process multiple properties at once.
* **Reduce**: Accumulates modifications from each element, pushing them onto an accumulator array. Useful for complex transformations or aggregations.
* **While loop**: Can be faster due to the absence of explicit loop control overhead. However, it requires manual index management and can lead to bugs if not handled correctly.

**Library and Special JS Features**

There is no specific library mentioned in this benchmark definition. However, some libraries (e.g., Lodash) provide utility functions for iterating over arrays, which could be used to implement these approaches.

If the test case uses a special JavaScript feature or syntax, such as async/await or Promises, it would be noted here. Unfortunately, there are no examples of this in the provided benchmark definition.

**Alternatives**

Some alternative approaches to creating new properties on array elements might include:

* Using `Array.prototype.forEach()` and assigning values directly to the element object.
* Utilizing a library like Lodash or Ramda for functional programming tasks.
* Leveraging modern ES6+ features, such as arrow functions and spread operators, to simplify data manipulation.

Keep in mind that the choice of approach often depends on the specific requirements and constraints of your project.

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/80.0.3987.132 Safari/537.36

Browser/OS: Chrome 80 on Linux

View result in a separate tab

Test name	Executions per second
For	3.5 Ops/sec
Map	38.4 Ops/sec
Reduce	4.5 Ops/sec
Foreach	50.6 Ops/sec
For reversed	6.9 Ops/sec
while	3.5 Ops/sec

Related benchmarks:

Creating new property, 1 (version: 0)

Comparing performance of: For vs Map vs Reduce vs Foreach vs For reversed vs while

Created: 4 years ago by: Guest

Jump to the latest result

For

Map

Reduce

Foreach

For reversed

while

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):