Benchmark: const vs var vs let performance in loop version 2

Tests:

Var
var tmp; for(var i = 0;i < 500000;i++) { tmp = i * (i - 1) * (i + 1) * (i + 10); }
Const
for(var i = 0;i < 500000;i++) { const tmp = i * (i - 1) * (i + 1) + (i + 10); }
Let
let tmp; for(var i = 0;i < 500000;i++) { tmp = i * (i - 1) * (i + 1) + (i + 10); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Var
Const
Let

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Var	6925.7 Ops/sec
Const	6934.3 Ops/sec
Let	6929.4 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 benchmark and analyze what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark definition specifies that it measures the performance of `const`, `var`, and `let` variables in a loop. The script preparation code is empty, which means that the test will execute the provided JavaScript code snippets without any additional setup or cleanup.

**Individual Test Cases**

There are three test cases:

1. **Var**: This test case uses the traditional variable declaration syntax (`var tmp`) and assigns a value to `tmp` inside a loop.
2. **Const**: This test case uses the `const` keyword for variable declaration and initialization, which is more restrictive than `var`. The code snippet inside the loop does not reassign the value of `const tmp`.
3. **Let**: This test case uses the `let` keyword for variable declaration and assignment, which is similar to `var` but provides a block scope.

**Comparison Options**

The three options being compared are:

* `Var`: Traditional variable declaration syntax without block scope.
* `Const`: Variable declaration with block scope and constant initialization.
* `Let`: Variable declaration with block scope and dynamic initialization.

**Pros and Cons**

Here's a brief summary of the pros and cons for each option:

* **Var**: Easy to use, but can lead to variable hoisting issues and potential bugs due to its lack of block scope. This is an older syntax that was widely used before ES6.
* **Const**: Provides more safety and predictability by preventing reassignments. However, it can be less readable if not used correctly, as the compiler cannot infer the intended usage. This syntax is generally considered safer but may require more boilerplate code for some use cases.
* **Let**: Offers a balance between `var` and `const`, providing block scope while still allowing dynamic initialization. It's often preferred over `var` due to its safety features.

**Other Considerations**

When choosing between these options, consider the following:

* Readability: If you need to express complex logic or relationships between variables, `let` might be a better choice.
* Safety: If you want to prevent accidental reassignments or unexpected behavior, `const` is a good option. However, if you're using modern JavaScript with modern browsers, `let` is often sufficient due to its block scope and dynamic initialization capabilities.
* Compatibility: Keep in mind that older browsers might not support `let` or `const`. If you need to ensure compatibility across all browsers, you may need to use `var`.

**Library Usage**

There doesn't appear to be any explicit library usage in the benchmark code snippets.

**Special JS Features or Syntax**

None of the provided test cases utilize special JavaScript features like async/await, Promises, or modern syntaxes (e.g., arrow functions). The focus is on traditional variable declarations and loop performance.

**Alternative Benchmarks**

Other benchmarks that measure similar performance aspects might include:

* Loop performance with different data structures (arrays vs. objects)
* Memory allocation and deallocation
* Garbage collection benchmarks
* WebAssembly or native code performance

Keep in mind that these alternatives may focus on different aspects of JavaScript performance, such as memory management, garbage collection, or compiler optimization.

In summary, this benchmark measures the performance of `const`, `var`, and `let` variables in a loop, providing a comparison of traditional variable declaration syntaxes with block scope. The pros and cons of each option are discussed, along with considerations for readability, safety, compatibility, and library usage.

Related benchmarks:

const vs var vs let performance in loop version 2 (version: 0)

const vs var vs let performance in loop

Comparing performance of: Var vs Const vs Let

Created: one year ago by: Guest

Jump to the latest result

Var

Const

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):