Benchmark: const vs let vs var (fixed) 234

Tests:

var
var g = []; var f = function(x) { g.push(1,2,3) }; f()
let
let g = []; let f = function(x) { g.push(1,2,3) }; f()
const
const g = []; const f = function(x) { g.push(1,2,3) }; f()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
var
let
const

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:149.0) Gecko/20100101 Firefox/149.0

Browser/OS: Firefox 149 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
var	28076868.0 Ops/sec
let	23179148.0 Ops/sec
const	23154714.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the provided benchmark.

**Benchmark Overview**

The benchmark is designed to compare the performance of three JavaScript variable declarations: `const`, `let`, and `var`. The test cases are identical, except for the declaration type. Each test case consists of a function that pushes an array of numbers onto a global array using the declared variable.

**Options Compared**

The options being compared are:

1. **`const`**: A declaration that ensures the variable cannot be reassigned.
2. **`let`**: A declaration that allows reassignment, but not declaration reassignment (i.e., it can't be declared twice).
3. **`var`**: A declaration that has function scope and can be reassigned.

**Pros and Cons of Each Approach**

1. **`const`**:
	* Pros: Memory safety, performance benefits due to optimization by the JavaScript engine.
	* Cons: Reassignment is not allowed, which might require additional logic in code.
2. **`let`**:
	* Pros: Allows reassignment, suitable for functions that need to update variables.
	* Cons: Reassignment can lead to memory leaks if not managed properly.
3. **`var`**:
	* Pros: Wide compatibility and ease of use.
	* Cons: Potential performance issues due to variable hoisting and late binding.

**Library and Special Features**

None of the test cases explicitly use any libraries or special JavaScript features beyond standard syntax.

**Benchmark Preparation Code**

The provided `Script Preparation Code` is empty, which means that the benchmark assumes that no additional code is needed to prepare the script for execution. The `Html Preparation Code` is also empty.

**Alternative Benchmarks**

If you'd like to explore alternative benchmarks, here are a few examples:

* `Array.prototype.push() vs Array.prototype.length`: This benchmark compares the performance of two common array methods.
* `String concatenation vs template literals**: This benchmark tests the performance of string concatenation using the `+` operator versus template literals.
* `DOM mutations vs DOM updates`: This benchmark evaluates the performance of different approaches to updating the Document Object Model (DOM).

Keep in mind that these are just a few examples, and there are many other possible benchmarks depending on your specific interests and use cases.

I hope this explanation helps you understand the provided benchmark!

Related benchmarks:

const vs let vs var (fixed) 234 (version: 0)

Comparing performance of: var vs let vs const

Created: one year ago by: Guest

Jump to the latest result

var

let

const

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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