Benchmark: const vs let vs var (fixed) 2

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: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Mac OS X 10.15.7

View result in a separate tab

let

78.4M/s

const

77.9M/s

var

76.0M/s

View exact numbers

Test name	Executions per second
✓ let	78,444,160 Ops/sec
const	77,875,072 Ops/sec
var	76,046,832 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The provided JSON represents a benchmark definition for comparing the performance of `const`, `let`, and `var` in JavaScript. The benchmark is designed to test how these variables affect the execution speed of a specific code snippet.

Here's a breakdown of the options being compared:

* **`const`**: Declares a variable that cannot be reassigned.
* **`let`**: Declares a variable that can be reassigned, but not until after its declaration.
* **`var`**: Declares a variable that can be reassigned at any time.

**Pros and Cons of each approach:**

* **`const`**: Pros:
	+ Memory safety (variables cannot be reassigned).
	+ Compile-time optimization (constant variables are optimized by the compiler).
	Cons:
	+ Less flexible than `let` or `var`, as variables must be initialized at declaration.
* **`let`**: Pros:
	+ More flexible than `const`, as variables can be reassigned after declaration.
	+ Easier to use in loops, where variable assignments are common.
Cons:
	+ No compile-time optimization for reassignable variables.
* **`var`**: Pros:
	+ Most flexible option, with no restrictions on reassignment.
	+ Suitable for simple scripts or legacy code.
Cons:
	+ Performance impact due to reassignments (e.g., in loops).
	+ Memory safety concerns (reassignments can lead to unexpected behavior).

**Library and Purpose**

There is no explicit library mentioned in the benchmark definition. However, it's likely that the JavaScript engine being tested has built-in optimizations or features for handling variables.

**Special JS Features/Syntax**

None are explicitly mentioned in the provided benchmark definition.

**Other Alternatives**

Some alternative approaches to measuring variable performance include:

1. **Hoist**: Instead of comparing `const`, `let`, and `var`, hoisting could be compared. Hoist is a feature that moves variable declarations above their assignments, which can affect performance.
2. **Variable shadowing**: This involves reassigning variables within loops or recursive functions, which can impact performance due to the overhead of reassignment.

Keep in mind that these alternatives may require more complex benchmark definitions and are not directly related to the `const`, `let`, and `var` comparison provided on MeasureThat.net.

const vs let vs var (fixed) 2 (version: 0)

Comparing performance of: `var vs let vs const`

Created: 2 years ago by: Guest

Go 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):

const vs let vs var (fixed) 2 (version: 0)

Comparing performance of: var vs let vs const

Created: 2 years ago by: Guest

Go 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):

Related benchmarks

Comparing performance of: `var vs let vs const`