Benchmark: Array.push( spread ) vs assign Array.concat()

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.push( spread )
Array.concat()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.122 Safari/537.36

Browser/OS: Chrome 81 on Windows

View result in a separate tab

Test name	Executions per second
Array.push( spread )	27929518.0 Ops/sec
Array.concat()	5212591.5 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):

LLMs can make mistakes. Check important info.

This benchmark compares two ways to add elements from one array to another in JavaScript:

**Method 1:  `Array.push()` with the spread operator (`...`)**

- Code Example: `var other = [1, 2].push(...params);`
   - Explanation: This method uses the `push()` method on an existing array (`[1, 2]`). The spread operator (`...params`) expands the contents of the `params` array into individual elements, which are then added to the end of `other`.

**Method 2:  `Array.concat()`**

- Code Example: `var other = [1, 2].concat(params);`
   - Explanation: This method uses the `concat()` method on an existing array (`[1, 2]`). It takes another array (`params`) as an argument and creates a *new* array containing all elements from both input arrays.

**Pros and Cons:**

* **`Array.push()` with Spread Operator:**
    - **Pro:** Often faster because it modifies the existing array in place.
    - **Con:** Can be less readable for beginners who are unfamiliar with the spread operator.
* **`Array.concat()`:**
    - **Pro:** Creates a new array without modifying the original arrays, which can be helpful if you need to preserve the original data.
    - **Con:**  Generally slower than `push()` because it creates a new array.

**Alternatives:**

* **For in loops:** You could manually iterate through the elements of `params` and push each element into `other`. This is generally less efficient than using built-in methods.

**Key Considerations:**

* **Performance:** If speed is critical, `Array.push()` with the spread operator is often the most performant option.
* **Data Modification:** If you need to preserve the original arrays, use `Array.concat()`.

Let me know if you have any other questions!

Related benchmarks:

Array.push( spread ) vs assign Array.concat() (version: 0)

Comparing performance of: Array.push( spread ) vs Array.concat()

Created: 4 years ago by: Guest

Jump to the latest result

Array.push( spread )

Array.concat()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):