Benchmark: Local scope vs outer scope variables (fixed)

Script Preparation code:

var testVar = 10;

Tests:

Do not cache at all
function doTest1(){ var sum = 0; for (var i = 0; i < testVar; i++){ sum = sum + i; } } doTest1();
Cache in the inner scope
function doTest2(){ var sum = 0; var testVarLocal = testVar; for (var i = 0; i < testVarLocal; i++){ sum = sum + i; } } doTest2();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Do not cache at all
Cache in the inner scope

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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Let's dive into explaining the provided benchmark.

**What is tested:**

The benchmark measures the performance difference between two approaches when caching variable `testVar` in different scopes:

1. **Not caching at all**: In this approach, `testVar` is not declared within any function or scope, and its value is passed directly to the loop.
2. **Caching in the inner scope**: In this approach, `testVar` is declared within a nested function (`doTest2`) but still accessible outside of it due to variable hoisting.

**Options compared:**

The benchmark compares two options:

1. **Direct access to testVar**: The outer scope variable `testVar` is passed directly to the loop without caching.
2. **Caching in the inner scope**: The value of `testVar` is declared within a nested function, and its value is accessible outside of it due to variable hoisting.

**Pros and cons:**

1. **Not caching at all**:
	* Pros: Simple and straightforward approach, no overhead for caching.
	* Cons: May lead to slower performance since the loop iterates over `testVar` multiple times.
2. **Caching in the inner scope**:
	* Pros: Can improve performance by reusing the cached value, reducing iterations over `testVar`.
	* Cons: Introduces additional complexity due to variable hoisting and potential memory usage.

**Library and special JS feature:**

There are no libraries used in this benchmark. The only notable JavaScript feature used is **variable hoisting**, which allows variables declared within a function scope to be accessible outside of it, even if they are not yet initialized.

**Other alternatives:**

In general, caching mechanisms like memoization or closure-based approaches can also be used to optimize performance. However, the specific approach taken in this benchmark (caching in the inner scope) is more aligned with a traditional JavaScript optimization technique.

To further improve this benchmark, you could consider exploring other optimization techniques, such as:

* Using `let` or `const` instead of `var` for variable declarations.
* Avoiding unnecessary reassignments within the loop.
* Using iterative methods (e.g., `for...of`) over array methods like `forEach()`.

Keep in mind that these alternatives may introduce additional complexity and require more careful consideration to ensure optimal performance.

Related benchmarks:

Local scope vs outer scope variables (fixed) (version: 0)

Cache variable in the function scope

Comparing performance of: Do not cache at all vs Cache in the inner scope

Created: 9 years ago by: Registered User

Jump to the latest result

Do not cache at all

Cache in the inner scope

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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