Benchmark: Spread(...) vs Array.from

Tests:

Spread
const a = []; for(let i = 0; i < 100; ++i) { a[i] = i; } [...a];
Array.from
const a = []; for(let i = 0; i < 100; ++i) { a[i] = i; } Array.from(a);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread
Array.from

Fastest: N/A

Slowest: N/A

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

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Let's break down the provided benchmark definition and test cases.

**What is being tested?**

MeasureThat.net is testing two different ways to create an array from an existing array: using the spread operator (`...`) and `Array.from()`. The goal is to compare their performance, execution frequency per second, in a specific scenario where an array of 100 elements is populated with values and then converted to another array.

**Options compared**

Two options are being compared:

1. **Spread Operator (`...`)**: This operator creates a new array by spreading the elements of an existing array.
2. **Array.from()**: This method creates a new array from an existing iterable (such as an array, string, or object).

**Pros and Cons of each approach**

* **Spread Operator (`...`)**:
	+ Pros:
		- Concise and readable syntax
		- Works with most data types (arrays, strings, objects)
	+ Cons:
		- Can be slower due to the overhead of creating a new array
		- Not as efficient as `Array.from()` for large datasets
* **Array.from()**:
	+ Pros:
		- More efficient and optimized for performance
		- Allows specifying an initial population or other configuration options
	+ Cons:
		- Less concise syntax compared to spread operator
		- May not be as readable for simple use cases

**Library usage**

None of the provided test cases uses any external libraries. However, it's worth noting that `Array.from()` is a built-in JavaScript method.

**Special JS feature or syntax**

The only special JS feature used in this benchmark is the spread operator (`...`). The syntax `[...a];` creates a new array by spreading the elements of an existing array `a`.

**Other alternatives**

If you want to optimize performance for creating arrays, here are some alternative approaches:

1. **Using `Array()` constructor**: Instead of using `Array.from()`, you can create an empty array and push elements onto it using the array prototype's methods (e.g., `push()`).
```javascript
const a = [];
for (let i = 0; i < 100; ++i) {
  a.push(i);
}
```
2. **Using a loop with a `push`-like method**: If you're working in an older version of JavaScript that doesn't support the array constructor, you can use a loop with a push-like method (e.g., `slice()` and `concat()`) to create the array.
```javascript
const a = [];
for (let i = 0; i < 100; ++i) {
  a.push(i);
}
```
Keep in mind that these alternatives may not be as efficient or readable as using `Array.from()`.

**Benchmark preparation code**

The provided benchmark preparation code creates an empty array and populates it with values using a for loop. The resulting array is then used to test the spread operator (`[...a];`) and `Array.from(a);` approaches.

In conclusion, this benchmark helps you compare the performance of two popular ways to create arrays in JavaScript: using the spread operator (`...`) and `Array.from()`. By understanding the pros and cons of each approach, you can choose the most suitable method for your specific use case.

Related benchmarks:

Spread(...) vs Array.from (version: 0)

Comparing performance of: Spread vs Array.from

Created: 3 years ago by: Guest

Jump to the latest result

Spread

Array.from

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):