Benchmark: Array.from vs Object.assign vs Spread 2

Tests:

Array.from
const classList = ['a', 'b', 'c'] console.log(Array.from(classList))
Object.assign
const classList = ['a', 'b', 'c'] console.log(Object.assign([], classList))
Spread
const classList = ['a', 'b', 'c'] console.log([...classList])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.from
Object.assign
Spread

Fastest: N/A

Slowest: N/A

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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 benchmark and its test cases.

The benchmark is testing three different approaches to create an array from an existing iterable: `Array.from()`, `Object.assign()` with an empty array as the first argument, and the spread operator (`...`).

**Options being compared:**

1. **Array.from()**: This method takes an iterable (like a string or an array) as its first argument and returns a new array containing all elements of the iterable.
2. **Object.assign() with an empty array**: This approach uses `Object.assign()` to create a shallow copy of the input iterable by concatenating it with an empty array.
3. **Spread operator (`...`)**: The spread operator is used to expand an iterable (like an array or string) into individual elements.

**Pros and Cons of each approach:**

1. **Array.from()**:
	* Pros: Efficient, creates a new array, and can handle nested iterables.
	* Cons: May be slower than the spread operator for small arrays.
2. **Object.assign() with an empty array**:
	* Pros: Can handle large datasets and avoids creating a new array.
	* Cons: Slower than `Array.from()` and may create unnecessary intermediate objects (if not using `Object.assign()` correctly).
3. **Spread operator (`...`)**:
	* Pros: Fast, efficient, and creates a new array without the overhead of `Object.assign()`.
	* Cons: May be slower for very large datasets due to the creation of temporary arrays.

**Library used in test cases:**

None are explicitly mentioned, but the use of `Object.assign()` suggests that it is being used as part of the JavaScript standard library.

**Special JS feature or syntax used in test cases:**

The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2015 (ES6). It allows you to expand an iterable into individual elements.

**Other alternatives:**

1. **Array.prototype.slice()**: This method returns a shallow copy of the input array.
2. **Array.prototype.concat()**: This method concatenates two or more arrays and returns a new array.
3. **For loops**: You could use a traditional for loop to iterate over an iterable and create a new array.

In terms of alternatives, `Object.assign()` with an empty array is not as efficient or practical as the spread operator or `Array.from()`. The spread operator is generally considered the most efficient and modern way to create an array from an iterable.

Related benchmarks:

Array.from vs Object.assign vs Spread 2 (version: 0)

Comparing performance of: Array.from vs Object.assign vs Spread

Created: 3 years ago by: Guest

Jump to the latest result

Array.from

Object.assign

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):