Benchmark: global let vs local const_mohammadBaghaei

Tests:

local const
for (i = 0; i < 10000; i++) { const t = Math.floor(Math.random() * 1000) console.log(t); }
global let
let t; for (i = 0; i < 10000; i++) { t = Math.floor(Math.random() * 1000) console.log(t); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
local const
global let

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36

Browser/OS: Chrome 111 on Windows

View result in a separate tab

Test name	Executions per second
local const	1.7 Ops/sec
global let	1.7 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the JavaScript microbenchmark you've provided.

**What is being tested?**

The benchmark tests two different ways of declaring variables in JavaScript: `let` and `const`. Specifically, it compares the performance of `global let` (i.e., `let` declared outside any function or block) with `local const` (i.e., `const` inside a loop).

**Options compared**

There are two options being compared:

1. **Global let**: This is when you declare a variable using `let` outside any function or block, like this: `let t;`.
2. **Local const**: This is when you declare a constant variable inside a loop using `const`, like this: `for (i = 0; i < 10000; i++) { const t = Math.floor(Math.random() * 1000); console.log(t); }`.

**Pros and Cons of each approach**

1. **Global let**: This approach has some advantages:
	* It's more flexible, as you can reassign the value of `t` using `let`.
	* It's often used in global scope variables.
However, it also has some disadvantages:
	* It creates a new scope for `t`, which can lead to hoisting and other scoping issues.
	* In modern JavaScript engines, reassignment of `let` variables is optimized away at compile-time, so the difference between `let` and `const` might be negligible.
2. **Local const**: This approach has some advantages:
	* It's more predictable, as `t` can only be reassigned within the loop.
	* It's often used in situations where you need to create a new variable that shouldn't be modified outside the scope of the loop.

However, it also has some disadvantages:
	* It creates a new constant variable on every iteration, which can lead to memory allocation and deallocation overhead.
	* In older JavaScript engines or browsers, `const` variables might not be optimized away as efficiently as `let` variables.

**Library usage**

There is no explicit library mentioned in the benchmark definition or test cases. However, it's worth noting that some modern JavaScript engines use various optimization techniques, such as just-in-time (JIT) compilation and caching, to improve performance.

**Special JS features or syntax**

The benchmark uses `const` variables, which is a relatively recent feature introduced in ECMAScript 2015. It also uses `let` variables without the `var` keyword, which is a more modern way of declaring variables in JavaScript.

**Other alternatives**

Some alternative approaches to comparing performance could be:

1. Using different data structures, such as arrays or objects, instead of numbers.
2. Implementing different algorithms for the loop, such as nested loops or recursive functions.
3. Using different optimization techniques, such as memoization or caching.

However, these alternatives might not accurately represent real-world scenarios and may not be relevant to this specific benchmark.

Overall, the benchmark provides a simple and concise way to compare the performance of two common JavaScript variable declarations: `let` and `const`.

Related benchmarks:

global let vs local const_mohammadBaghaei (version: 0)

Comparing performance of: local const vs global let

Created: one year ago by: Registered User

Jump to the latest result

local const

global let

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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