Benchmark: Const vs VAR vs LET full

Tests:

Const
const limit = 10000; const A = function (result){ const a = result + 1; if (a < limit){ return A(a); } } A(0)
VAR
var limit = 10000; var A = function (result){ var a = result + 1; if (a < limit){ return A(a); } } A(0)
LET
let limit = 10000; let A = function (result){ let a = result + 1; if (a < limit){ return A(a); } } A(0)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Const
VAR
LET

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser/OS: Chrome 103 on Linux

View result in a separate tab

Test name	Executions per second
Const	15812.0 Ops/sec
VAR	16787.1 Ops/sec
LET	15709.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros/cons.

**What is being tested?**

The test cases are designed to compare the performance of three different variable declarations in JavaScript: `const`, `var`, and `let`. Each test case defines a recursive function `A` that increments its result until it reaches a predefined limit (`limit`). The tests measure how many times each function executes per second on different browsers.

**Options compared**

The main options being compared are:

1. **`const`**: A variable declaration that makes the variable immutable, meaning its value cannot be changed after declaration.
2. **`var`**: A variable declaration that is function-scoped and does not declare the variable's scope.
3. **`let`**: A variable declaration that is block-scoped, which means it only has access to the code within its surrounding `let` block.

**Pros/Cons of each approach**

1. **`const`**:
	* Pros: Faster execution times due to constant evaluation and caching by JavaScript engines.
	* Cons: Variables declared with `const` cannot be reassigned, which might limit its use in certain scenarios.
2. **`var`**:
	* Pros: Widely supported and compatible across older browsers.
	* Cons: Slower execution times compared to `const` due to slower variable evaluation and caching.
3. **`let`**:
	* Pros: Block-scoped, which can improve code readability and maintainability.
	* Cons: Slower execution times compared to `const`, but only in situations where block scoping is beneficial.

**Libraries used**

None of the test cases use any external libraries or frameworks that would affect the results.

**Special JS feature/syntax**

There's no specific JavaScript feature or syntax being tested beyond the variable declarations. However, it's worth noting that this benchmark focuses on the performance differences between `const`, `var`, and `let` due to their scoping behavior.

**Other alternatives**

If you'd like to explore other variable declaration options in JavaScript, consider:

* **`let const`**: A shorter syntax for declaring both variables at once (e.g., `let x = 0; const y = x * 2;`).
* **`var with the 'with' statement'**: An older technique that allows you to reuse a variable by creating a new scope using the `with` statement. However, this is not recommended due to performance and compatibility issues.

Keep in mind that these alternatives are not being tested in this specific benchmark.

Related benchmarks:

Const vs VAR vs LET full (version: 0)

Const vs VAR vs LET full

Comparing performance of: Const vs VAR vs LET

Created: 2 years ago by: Registered User

Jump to the latest result

Const

VAR

LET

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):