Benchmark: Array.prototype.concat vs spread operator(push) vs for of

Script Preparation code:

var arr = Array(100).fill([{n: ''}]);
var arr2 = Array(100).fill([{n: ''}]);

Tests:

Array.prototype.concat
var other = arr.concat(arr2);
spread operator
arr.push(...arr2); var other = arr;
array.push
for(let item of arr2) { arr.push(item); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator
array.push

Fastest: N/A

Slowest: N/A

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Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

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**Benchmark Description**

The provided JSON represents a benchmark test case on MeasureThat.net, which compares the performance of three different methods for concatenating two arrays in JavaScript: `Array.prototype.concat`, the spread operator (`push` with spread syntax), and a simple `for...of` loop followed by `push`.

**Test Cases**

1. **`Array.prototype.concat`**: This test case uses the traditional `concat()` method to concatenate two arrays, `arr` and `arr2`. The benchmark definition is `var other = arr.concat(arr2);`.
2. **Spread Operator (`push` with spread syntax)**: This test case uses the spread operator (`...`) to concatenate `arr2` into `arr`, followed by assigning the modified `arr` to a new variable, `other`. The benchmark definition is `arr.push(...arr2);\r\nvar other = arr;`.
3. **`array.push`**: This test case uses a simple `for...of` loop to iterate over `arr2` and push each item into `arr`, followed by assigning the modified `arr` to a new variable, `other`. The benchmark definition is `for(let item of arr2) {\r\n  arr.push(item);\r\n}\r\n`.

**Library/Feature Used**

None specifically mentioned in this test case.

**Options Compared**

The three options being compared are:

1. **`Array.prototype.concat`**: A traditional method for concatenating arrays.
2. **Spread Operator (`push` with spread syntax)**: A concise and expressive way to concatenate arrays using the `...` operator.
3. **`array.push`**: A simple loop-based approach to concatenate arrays by pushing each item from one array into another.

**Pros/Cons of Each Approach**

1. **`Array.prototype.concat`**:
	* Pros: Easy to read, well-established method for concatenating arrays.
	* Cons: May be slower than other methods due to the overhead of a function call.
2. **Spread Operator (`push` with spread syntax)**:
	* Pros: Concise and expressive syntax, often faster than `concat()` due to the elimination of function calls.
	* Cons: May not be as readable or intuitive for developers unfamiliar with the spread operator.
3. **`array.push`**:
	* Pros: Simple loop-based approach, may be suitable for small arrays or specific use cases.
	* Cons: Can be slower than other methods due to the overhead of a loop and multiple function calls.

**Other Considerations**

When choosing an approach, consider factors such as:

1. **Code Readability**: Choose a method that is easy to read and understand for yourself and others.
2. **Performance**: If performance is critical, use the spread operator or `concat()` over a simple loop-based approach.
3. **Array Size**: For very large arrays, using the spread operator or `concat()` may be more efficient than a simple loop.

**Other Alternatives**

1. **`set` and `Map` objects**: In some cases, using `Set` or `Map` objects to concatenate arrays can provide better performance.
2. **Array methods like `flat()` and `flatMap()`**: These methods can simplify the concatenation process for specific use cases.

I hope this explanation helps you understand the benchmark test case!

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Comparing performance of: Array.prototype.concat vs spread operator vs array.push

Created: 6 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

array.push

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):