Benchmark: Testing Var vs Return

Tests:

Var
function test1(){ const x = 1+1; return x; }
No var
function test1(){ return 1+1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Var
No var

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36

Browser/OS: Chrome 83 on Linux

View result in a separate tab

Test name	Executions per second
Var	523226656.0 Ops/sec
No var	515813632.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript microbenchmark on MeasureThat.net and explain what's being tested, compared, and other considerations.

**What is being tested?**

The benchmark measures the performance difference between two approaches: using the `var` keyword to declare variables versus not declaring them at all (i.e., using function scope).

**Options compared:**

Two options are being compared:

1. **Var**: This option uses the `var` keyword to declare a variable inside the function.
2. **No var**: This option does not use the `var` keyword, effectively using function scope instead.

**Pros and Cons of each approach:**

* **Var**: The pros of this approach are that it provides explicit declaration and scoping for variables, making the code easier to read and understand. However, in older browsers or environments with limited JavaScript support, the `var` keyword may not be supported.
* **No var**: This approach is more concise and can be faster because it avoids the overhead of declaring a variable using `var`. However, it also means that variable declarations are implicit, which can make the code harder to understand and maintain.

**Other considerations:**

In JavaScript, variables declared with `var` have function scope, while variables declared without `var` (or using `let` or `const`) have block scope. This means that in a single function, variables declared without `var` are only accessible within the function's body, whereas those declared with `var` are accessible throughout the entire function.

**Library usage:**

None of the benchmark cases use any JavaScript libraries.

**Special JS features or syntax:**

The benchmark uses some implicit variable scoping rules in modern browsers. Specifically, it relies on the fact that variables declared without `var`, `let`, or `const` have block scope. This is a feature introduced in ECMAScript 2015 (ES6) and is supported by most modern JavaScript engines.

**Benchmark preparation code:**

The provided benchmark preparation code is empty, which means that MeasureThat.net likely generates this code automatically based on the benchmark definition.

**Alternatives:**

Other alternatives to measure variable declaration performance could include:

1. Measuring the impact of `var`, `let`, or `const` on memory usage.
2. Comparing the execution speed of different variable declaration patterns in various JavaScript engines or environments.
3. Testing the performance of code with explicit and implicit variable declarations in different contexts (e.g., within loops, conditionals, etc.).

These alternative benchmarks could provide more comprehensive insights into the performance implications of variable declaration choices in JavaScript.

Related benchmarks:

Testing Var vs Return (version: 0)

Comparing performance of: Var vs No var

Created: 4 years ago by: Guest

Jump to the latest result

Var

No var

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):