Benchmark: Storing a temporary variable vs repeated function call

Script Preparation code:

var temp = "test";
function func() {
  return temp;  
}

Tests:

function call
for(var i=0; i<100000; i++) { var local = func(); if(local == "test") { console.log("test"); } }
local variable
var local = func(); for(var i=0; i<100000; i++) { if(local == "test") { console.log("test"); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
function call
local variable

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the JavaScript microbenchmark provided by MeasureThat.net.

**Benchmark Definition**

The benchmark is designed to test two different approaches:

1. **Storing a temporary variable**: This approach involves assigning the result of `func()` to a local variable `local` and then using this variable in an if statement.
2. **Repeated function call**: This approach involves calling `func()` repeatedly 100,000 times without storing its result in any variable.

**Options being compared**

The benchmark is comparing two different strategies for evaluating the expression inside `func()`. The options are:

* Storing a temporary variable (`local`) and using it to evaluate the expression.
* Repeatedly calling `func()` without storing its result in any variable.

**Pros and Cons of each approach**

1. **Storing a temporary variable**
	* Pros:
		+ Can be faster because the expression is only evaluated once, when the variable is assigned.
		+ Avoids potential side effects or modifications to global variables inside `func()`.
	* Cons:
		+ Requires an extra assignment operation, which can be slower than simply evaluating the expression directly.
2. **Repeated function call**
	* Pros:
		+ No extra assignment operations are required, making it potentially faster.
	* Cons:
		+ The expression is evaluated 100,000 times, which can lead to significant overhead due to repeated function calls and potential side effects.

**Library and special JS feature**

There is no explicit library mentioned in the benchmark definition. However, `func()` appears to be a custom function that returns a value.

If we assume `func()` is a simple function like this:

```javascript
function func() {
  return "test";
}
```

Then the benchmark is testing how efficiently JavaScript evaluates the expression `"test"`. This is likely due to how JavaScript's interpreter handles function calls and variable assignments, which can affect performance.

**Considerations**

When writing benchmarks like this, it's essential to consider factors such as:

* The specific hardware and software environment being tested.
* Potential side effects or modifications to global variables inside `func()`.
* The overhead of repeated function calls versus a single evaluation.
* The importance of readability and maintainability in the benchmark code.

**Alternatives**

Other alternatives for evaluating expressions like this might include:

* Using a more concise syntax, such as `return 'test';` instead of `function func() { return 'test'; }`.
* Utilizing JavaScript's `eval()` function or other built-in functions that can evaluate expressions directly.
* Writing the benchmark in a language with stronger type checking and optimization capabilities, such as C++.

Keep in mind that each alternative may come with its own set of trade-offs and potential performance implications.

Related benchmarks:

Storing a temporary variable vs repeated function call (version: 0)

Comparing performance of: function call vs local variable

Created: 9 years ago by: Guest

Jump to the latest result

function call

local variable

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):