Benchmark: Array.prototype.concat vs spread operator fork

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);
spread operator
var params = [ "hello", true, 7 ] var other = [ 1, 2, ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0

Browser/OS: Firefox 140 on Linux

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Test name	Executions per second
Array.prototype.concat	16654597.0 Ops/sec
spread operator	17388382.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 months ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON compares two ways of merging arrays in JavaScript: the traditional `Array.prototype.concat` method and the newer ES6 spread operator. Here’s a breakdown of what is being tested and the implications of each approach.

### Benchmark Overview

1. **Test Name:**
   - **Array.prototype.concat**
   - **Spread Operator**

2. **Purpose of Benchmark:**
   - The benchmark aims to evaluate the performance differences between using `concat()` and the spread operator for merging arrays.

### 1. Array.prototype.concat

- **Definition:** 
   ```javascript
   var params = [ "hello", true, 7 ];
   var other = [ 1, 2 ].concat(params);
   ```
- **Functionality:** 
   - The `concat()` method creates a new array by combining two or more arrays or values. It does not change the existing arrays but returns a new one.

**Pros:**
- Readability: For developers familiar with the method, the intent is clear.
- Functional: It explicitly shows that you are combining two arrays.

**Cons:**
- Performance: In some cases, particularly with larger arrays, `concat()` may be slower than the spread operator.
- Verbose: Requires more syntax compared to the spread operator.

### 2. Spread Operator

- **Definition:** 
   ```javascript
   var params = [ "hello", true, 7 ];
   var other = [ 1, 2, ...params ];
   ```
- **Functionality:** 
   - The spread operator (`...`) allows an iterable, such as an array, to be expanded in places where zero or more arguments or elements are expected. In this case, it merges the `params` array into the new array directly.

**Pros:**
- Conciseness: Shorter syntax leads to more readable code for simple array merging operations.
- Performance: In the provided benchmark results, the spread operator shows a higher execution rate, indicating that it may perform better in this specific use case.

**Cons:**
- Learning Curve: Developers who are not familiar with ES6 features may find it confusing or less intuitive.
- Compatibility: Older environments (pre-ES6) may not support the spread operator without transpilation.

### Benchmark Results Summary

- **Results:**
   - Spread Operator: **17,388,382 Executions per Second**
   - Array.prototype.concat: **16,654,597 Executions per Second**
  
From the results, you can see that the spread operator performs better than the `concat()` method in the tested environment, indicating a possible performance benefit when using the spread operator for merging arrays.

### Other Considerations and Alternatives

1. **Performance:** 
   - Performance can vary based on the size of the arrays and the specific JavaScript engine being used (such as V8 in Chrome, SpiderMonkey in Firefox, etc.).
  
2. **Use Cases:** 
   - For simply merging arrays, the spread operator may be preferred for its conciseness and potential performance advantages. However, if you need to maintain the immutability of arrays or are working with external libraries that manipulate arrays heavily, `concat()` can be useful.

3. **Alternatives:**
   - **Array.prototype.push() with apply()/spread()**: You can also use `push()` along with `apply()` or the spread operator to add elements from one array to another.
   - **Array merging libraries**: Libraries like Lodash have utility functions such as `_.concat` that provide additional features and safety checks when merging arrays.

In summary, developers should weigh the readability and compatibility of each approach against performance metrics when choosing between `Array.prototype.concat` and the spread operator for array merging tasks in JavaScript.

Related benchmarks:

Array.prototype.concat vs spread operator fork (version: 1)

Compare the new ES6 spread operator with the traditional concat() method

Comparing performance of: Array.prototype.concat vs spread operator

Created: 6 months ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 months ago):