Benchmark: Array concat vs spread operator vs push + spread 2023-08-21

Tests:

Array.prototype.concat
var params = Array(1500).fill(0); params = [ 1 ].concat(params);
spread operator
var params = Array(1500).fill(0); params = [ 1, ...params ];
Push
var params = Array(1500).fill(0); [1].push(...params);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator
Push

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser/OS: Chrome 117 on Linux

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	279399.6 Ops/sec
spread operator	73091.6 Ops/sec
Push	161744.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided benchmark definition compares three approaches for concatenating an array in JavaScript:

1.  The traditional `Array.prototype.concat()` method.
2.  The new ES6 spread operator (`...`).
3.  The `push` method with a spread operator (`[1].push(...params)`).

**Options compared:**

The benchmark tests the following options:

*   `Array.prototype.concat()`: This is a built-in method that concatenates two arrays.
*   Spread operator (`...`): This operator was introduced in ES6 and allows for "spread" of array elements into a new array or as arguments to a function.
*   `push` with spread operator (`[1].push(...params)`): This approach uses the `push` method to add elements to an array, followed by the spread operator to concatenate the existing array.

**Pros and Cons:**

Here's a brief overview of each option:

### Array.prototype.concat()

**Pros:**

*   Well-established method with broad support.
*   Easy to understand for developers familiar with traditional JavaScript syntax.

**Cons:**

*   May have slower performance due to the overhead of creating a new array.
*   Less efficient in terms of memory usage, as it creates a new array object.

### Spread Operator (`...`)

**Pros:**

*   Modern and concise syntax that's widely adopted in modern JavaScript development.
*   Can be more readable and maintainable for developers familiar with this syntax.

**Cons:**

*   Requires ES6 support or newer.
*   May not work as expected in older browsers or environments without support for the spread operator.

### push with Spread Operator (`[1].push(...params)`)

**Pros:**

*   Can be more efficient than `concat()` since it avoids creating a new array object.
*   Supports both modern and older browsers/environments.

**Cons:**

*   Less readable and maintainable compared to the spread operator syntax.
*   Requires using `push` explicitly, which may not be as intuitive for some developers.

**Other Considerations:**

In addition to these options, it's worth noting that other approaches could also be considered in this benchmark. These might include:

*   Using `Array.prototype.push.apply()`, which is an optimized version of the `push()` method.
*   Implementing a custom concatenation function using loops or other optimized algorithms.
*   Testing different array sizes and configurations to observe variations in performance.

**Library/Function Used:**

None are explicitly mentioned, but it's possible that some libraries or frameworks might provide optimized implementations for these operations. However, without further context, no specific library or function can be identified.

**Special JS Features/Syntax:**

The benchmark uses the following features:

*   ES6 spread operator (`...`).
*   ES6 template literals (not explicitly used in this case, but relevant to the overall syntax).

These features are widely adopted and supported in modern JavaScript environments. If the benchmark were running in an older environment without support for these features, additional considerations would be necessary.

**Alternatives:**

Some possible alternatives for optimizing array concatenation include:

*   Using `Array.prototype.set()`, which is a more efficient method for large datasets.
*   Implementing custom algorithms using loops or other optimized techniques.
*   Leveraging browser-specific optimizations, such as WebAssembly or native code acceleration (if applicable).

However, without further context on the specific requirements and constraints of this benchmark, these alternatives remain speculative.

Related benchmarks:

Array concat vs spread operator vs push + spread 2023-08-21 (version: 0)

Compare the new ES6 spread operator with the traditional concat() method and push

Comparing performance of: Array.prototype.concat vs spread operator vs Push

Created: one year ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

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):