Benchmark: Javascript Concat vs Spread vs Push

Script Preparation code:

function getParams() {
    return Array(10000).fill().map(() => {
        return Math.floor(Math.random() * 1000) + 1;
    });
}
var params = getParams();

Tests:

Concat
var concat = [ 1, 2 ].concat(params);
Spread
var spread = [ 1, 2, ...params ];
Push
var push = [ "hello", true, 7 ]; push.push(params);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Concat
Spread
Push

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark, called "Javascript Concat vs Spread vs Push", compares the performance of three different ways to concatenate arrays in JavaScript: using the `concat()` method, the spread operator (`...`), and the `push()` method.

**Options Compared**

1. **Concat() Method**: This is a traditional way to concatenate arrays by calling the `concat()` method on an existing array.
2. **Spread Operator (ES6+)**: This is a newer way to concatenate arrays introduced in ECMAScript 2015. It uses the spread operator (`...`) followed by the array being concatenated.
3. **Push() Method**: This approach creates a new array and then pushes all elements from another array into it using the `push()` method.

**Pros and Cons of Each Approach**

1. **Concat() Method**
	* Pros: Widely supported in older browsers, easy to understand and implement.
	* Cons: Can be slower than other methods due to its overhead and copying mechanism.
2. **Spread Operator (ES6+)"
	* Pros: Fast, modern syntax, and efficient for large arrays.
	* Cons: Requires support for ES6+ features in older browsers or JavaScript environments.
3. **Push() Method**
	* Pros: Efficient and fast, especially for smaller arrays.
	* Cons: Requires creating a new array and pushing elements, which can be slower for very large arrays.

**Library and Syntax**

None of the test cases use any external libraries or special JS features beyond the ES6+ syntax for the spread operator. The code only uses built-in JavaScript methods and data structures.

**Benchmark Test Case Analysis**

The benchmark test case is designed to measure the performance of each approach by generating a large array (`params`) with random elements and then concatenating it to an initial array using one of the three methods. The test case repeats this process multiple times, measuring the time taken for each execution per second.

**Benchmark Results Interpretation**

The benchmark results show that:

* **Push() Method**: Fastest execution time (44961828.0 executions/second)
* **Concat() Method**: Slower than Push but faster than Spread (5290.435546875 executions/second)
* **Spread Operator (ES6+)**: Slowest execution time (4623.96923828125 executions/second)

The results suggest that the `push()` method is the most efficient way to concatenate arrays in JavaScript, followed by the traditional `concat()` method and then the newer spread operator.

**Other Alternatives**

Some other alternatives for concatenating arrays include:

* Using a library like Lodash (e.g., `_.union()`)
* Using an array comprehension or map function with `Array.prototype.concat()`
* Using a loop to manually iterate over elements and add them to an array

However, these alternatives may have different performance characteristics and may not be as efficient as the optimized methods used in this benchmark.

Related benchmarks:

Javascript Concat vs Spread vs Push (version: 0)

Compare concat/spread/push

Comparing performance of: Concat vs Spread vs Push

Created: 6 years ago by: Guest

Jump to the latest result

Concat

Spread

Push

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):