Benchmark: map vs spread - MeasureThat.net

Tests:

map
const a = new Array(10000); const b = a.map(l => l);
spread
const a = new Array(10000); const b = [...a];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
spread

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark definition is a JSON object that contains information about the test. In this case, it's relatively simple:

* `Name`: The name of the benchmark, which is "map vs spread".
* `Description`: An empty string, indicating that there's no description provided.
* `Script Preparation Code` and `Html Preparation Code`: Both are empty strings, suggesting that no code or HTML is required to prepare for the test.

**Individual Test Cases**

The benchmark consists of two individual test cases:

1. **map**: This test case uses the `.map()` method to create a new array from an existing one.
	* The `Benchmark Definition` script:
```javascript
const a = new Array(10000);
const b = a.map(l => l);
```
	* This creates a new array `a` with 10,000 elements and then uses the `.map()` method to create a new array `b`. The callback function `(l => l)` simply returns each element as is.
2. **spread**: This test case uses the spread operator (`...`) to create a new array from an existing one.
	* The `Benchmark Definition` script:
```javascript
const a = new Array(10000);
const b = [...a];
```
	* Similar to the `.map()` method, this creates a new array `b` by taking each element of `a` and using it as-is.

**Options Compared**

In this benchmark, we have two options being compared:

1. **`.map()`**: A built-in method for creating a new array from an existing one, with the benefit of performing some optimizations under the hood (e.g., avoiding unnecessary allocations).
2. **Spread operator (`...`)**: A more recent addition to JavaScript, introduced in ES6, which allows for efficient and concise creation of arrays.

**Pros and Cons**

Here are some pros and cons of each approach:

* `.map()`:
	+ Pros:
		- Optimizations under the hood (e.g., avoiding unnecessary allocations)
		- Can be more readable and maintainable
	+ Cons:
		- May have slower performance compared to the spread operator in modern JavaScript engines
* Spread operator (`...`):
	+ Pros:
		- More concise and expressive
		- Often faster performance than `.map()` due to its ability to avoid unnecessary allocations
	+ Cons:
		- Requires a minimum version of JavaScript (ES6+) to be supported

**Library Used**

None are explicitly mentioned, but the spread operator is a built-in feature of modern JavaScript.

**Special JS Features or Syntax**

The spread operator (`...`) is a relatively new addition to JavaScript and was introduced in ES6. It's designed for efficient and concise creation of arrays from existing ones.

Other alternatives that could be considered for this benchmark:

* Other methods, like `forEach()` or `reduce()`, might also create new arrays, but they would likely have different performance characteristics compared to `.map()` and the spread operator.
* Native WebAssembly support could potentially provide an alternative way to perform operations on arrays, especially if optimized for specific use cases.

Keep in mind that this is a microbenchmark focused on creating new arrays from existing ones. Other aspects of JavaScript might have different optimization strategies or performance characteristics.

Related benchmarks:

map vs spread (version: 0)

Comparing performance of: map vs spread

Created: 6 years ago by: Guest

Jump to the latest result

map

spread

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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