Benchmark: let vs const v2 - MeasureThat.net

Tests:

let
let groups = []; groups.push({a: 10, b:20})
const
const groups = []; groups.push({a: 10, b:20})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
let
const

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/118.0.0.0 Safari/537.36

Browser/OS: Chrome 118 on Linux

View result in a separate tab

Test name	Executions per second
let	53277696.0 Ops/sec
const	54016044.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data to understand what is being tested and the options compared.

**Benchmark Definition**

The benchmark definition is a simple JavaScript code snippet that creates an array `groups` using either the `let` or `const` keyword. The purpose of this benchmark is to compare the performance of declaring a variable with these two keywords in JavaScript.

**Options Compared**

Two options are being compared:

1. **Let**: Declaring a variable with the `let` keyword.
2. **Const**: Declaring a variable with the `const` keyword.

**Pros and Cons of Each Approach**

* **Let**:
	+ Pros: Allows reassignment of the variable, which can be useful in certain situations.
	+ Cons: Can lead to memory leaks if not handled properly, as variables are garbage collected when they go out of scope.
* **Const**:
	+ Pros: Ensures that the variable is immutable, making it easier to reason about code and reducing the risk of bugs caused by unintended modifications.
	+ Cons: Does not allow reassignment of the variable, which can limit its usefulness in certain situations.

**Library or Syntax Used**

None are explicitly mentioned in the provided JSON data. However, it's worth noting that modern JavaScript implementations, including those used by Chrome 118, support the `const` keyword for declaring variables, making it a more modern and idiomatic way to declare variables.

**Special JS Feature or Syntax (Not Applicable)**

Since neither of the benchmark definitions uses any special JavaScript features or syntax (such as async/await, Promises, or Web Workers), no additional explanation is necessary.

**Other Alternatives**

If you wanted to compare other options for declaring variables in JavaScript, some alternatives could include:

* **Var**: An older keyword that declares a variable without specifying its scope. While not recommended in modern code due to potential issues with scope and hoisting.
* **Let/Const with Initializers**: Declaring a variable using the `let` or `const` keyword followed by an initializer, like `let groups = []` or `const groups = () => { ... }`. This can help avoid common pitfalls related to uninitialized variables.

In summary, this benchmark compares the performance of declaring variables using the `let` and `const` keywords in JavaScript, with a focus on their impact on performance. The use of `const` is considered more modern and idiomatic, but both options have their trade-offs in terms of functionality and usability.

Related benchmarks:

let vs const v2 (version: 0)

Comparing performance of: let vs const

Created: 2 years ago by: Guest

Jump to the latest result

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):