Benchmark: Array .push() vs .unshift() with random numbers

Script Preparation code:

var arr = []

Tests:

.unshift()
for (let i = 0; i < 10000; i++) { arr.unshift(Math.random()) }
.push()
for (let i = 0; i < 10000; i++) { arr.push(Math.random()) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.unshift()
.push()

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36

Browser/OS: Chrome 83 on Mac OS X 10.15.4

View result in a separate tab

Test name	Executions per second
.unshift()	2.4 Ops/sec
.push()	358.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided benchmark measures the performance difference between two JavaScript methods: `arr.push()` and `arr.unshift()`, specifically when used to add random numbers to an array.

**What is being tested?**

The benchmark compares how fast it takes for each method to add 10,000 random numbers to an array. The `push()` method adds elements to the end of the array, while the `unshift()` method adds elements to the beginning of the array.

**Options compared:**

There are two options being compared:

1. **`arr.push(Math.random())`**: This method adds a random number to the end of the array using the `push()` method.
2. **`arr.unshift(Math.random())`**: This method adds a random number to the beginning of the array using the `unshift()` method.

**Pros and Cons:**

* **`push()` method:** Pros:
	+ More efficient when adding elements to the end of an array, as it only requires updating the length property of the array.
	+ Can be faster than `unshift()` for large arrays.
* **`unshift()` method:** Pros:
	+ Faster for small arrays or when adding elements to the beginning of the array, as it only requires shifting existing elements.
	+ Can be more efficient when inserting elements at arbitrary positions in an array.

Cons:

* **`push()` method:**
	+ Requires updating the length property of the array, which can be slower than updating individual element positions.
	+ May incur additional overhead due to the need for bounds checking when adding elements to the end of the array.
* **`unshift()` method:**
	+ Requires shifting existing elements, which can be slower than updating individual element positions.
	+ May incur additional overhead due to the need for bounds checking when adding elements to the beginning of the array.

**Library usage:**

None of the provided benchmark code uses any external libraries. The `Math.random()` function is used to generate random numbers, which is a built-in JavaScript function.

**Special JS features or syntax:**

No special JavaScript features or syntax are being used in this benchmark. The code only uses standard JavaScript syntax and features.

**Alternatives:**

Other alternatives to measure the performance difference between `push()` and `unshift()` methods might include:

1. Using a different data structure, such as an array with a fixed size.
2. Using a linked list or other dynamic data structure instead of an array.
3. Measuring the performance of other array methods, such as `splice()`, `concat()`, or `indexOf()`.
4. Comparing the performance of different programming languages or frameworks.

Keep in mind that the choice of alternative benchmark depends on the specific use case and requirements.

Related benchmarks:

Array .push() vs .unshift() with random numbers (version: 0)

Comparing performance of: .unshift() vs .push()

Created: 4 years ago by: Guest

Jump to the latest result

.unshift()

.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):