Benchmark: Array.from() vs new Array() vs push pushup

Tests:

new Array()
new Array(500).fill("push-up", 0, 500)
Array.from()
Array.from({ length: 500 }, () => "push-up")
push
let array = []; for (let i = 0; i < 500; i++){ array.push("push-up") }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Array()
Array.from()
push

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Windows

View result in a separate tab

Test name	Executions per second
new Array()	609595.7 Ops/sec
Array.from()	27223.9 Ops/sec
push	465561.6 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Overview**

The test cases aim to compare the performance of three approaches for creating filled arrays in JavaScript:

1. `new Array()`
2. `Array.from()`
3. `push` method (manual array creation)

**Test Cases Breakdown**

1. **`new Array(500).fill("push-up", 0, 500)`**: This test case creates a new array with 500 elements, filling it with the string "push-up". The first parameter to `Array.fill()` sets the initial value, while the second parameter specifies the number of times to repeat that value.
2. **`Array.from({ length: 500 }, () => "push-up")`**: This test case uses the `Array.from()` method with a generator function that returns the string "push-up". The `{ length: 500 }` object defines the length of the resulting array.
3. **`let array = []; for (let i = 0; i < 500; i++) { array.push("push-up"); }`**: This test case creates an empty array and then uses a `for` loop to push the string "push-up" onto the array 500 times.

**Options Comparison**

The three approaches have different characteristics:

* **`new Array()`**: Creates a new, empty array and can be optimized by the engine. This approach is simple and easy to read but might not be as efficient.
* **`Array.from()`**: A more modern approach that uses a factory function (the generator function in this case) to create an array. This method is often faster than `push` because it avoids creating temporary variables and can utilize various optimizations provided by the engine.
* **`push` method**: A manual approach that creates an empty array and then pushes elements onto it using the `push()` method. This approach requires more code and may not be as efficient due to the creation of a new array object and the need for multiple assignments.

**Pros and Cons**

* **`new Array()`**:
	+ Pros: Simple, easy to read
	+ Cons: Might not be optimized by the engine
* **`Array.from()`**:
	+ Pros: Often faster than `push`, can utilize optimizations
	+ Cons: Requires modern JavaScript (ES6+) and a factory function
* **`push` method**:
	+ Pros: Simple, easy to understand for some developers
	+ Cons: More code required, may not be optimized

**Other Considerations**

* The test cases use Chrome 122 as the browser. Different browsers might have varying performance due to engine optimizations or implementation differences.
* The test cases are run on a desktop platform. Mobile devices and other platforms might have different performance characteristics.

**Alternatives**

If you're interested in exploring alternative approaches, consider:

* Using `new Array()` with `fill()` instead of `Array.from()`
* Implementing a custom array creation function using `Buffer` or `TypedArray`
* Using other modern JavaScript features like `Map` or `Set` for array-like objects

Keep in mind that the performance differences between these approaches may vary depending on the specific use case and environment.

Related benchmarks:

Array.from() vs new Array() vs push pushup (version: 0)

Testing the difference between creating filled arrays.

Comparing performance of: new Array() vs Array.from() vs push

Created: 9 months ago by: Guest

Jump to the latest result

new Array()

Array.from()

push

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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