Benchmark: const vs let vs var (fixed) 234

Tests:

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

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()

 
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()

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
var
let
const

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Linux

View result in a separate tab

Test name	Executions per second
var	22122902.0 Ops/sec
let	27144858.0 Ops/sec
const	25696414.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 5 months ago):

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:

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

Pros and Cons of Each Approach

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.
let:
- Pros: Allows reassignment, suitable for functions that need to update variables.
- Cons: Reassignment can lead to memory leaks if not managed properly.
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!

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: 9 months ago by: Guest

Jump to the latest result

var

let