Benchmark: Return true vs empty body

Script Preparation code:

var notDefined;
var defined = 1;

var emptyFunc = function() {};
var trueFunc = function() { return true; }
var undefinedFunc = function() { return undefined; }
var nullFunc = function() { return null; }
var notDefinedFunc = function() { return notDefined; }
var definedFunc = function() { return defined; }
var staticFunc = function() { return 1; }
var localUndefinedFunc = (function() {
  var notDefinedAgain;
  
  return function() {
  	return notDefinedAgain;
  }
})();

Tests:

localUndefinedFunc
localUndefinedFunc();
wrapped localUndefinedFunc
(localUndefinedFunc())

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
localUndefinedFunc
wrapped localUndefinedFunc

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Browser/OS: Chrome 53 on Windows 7

View result in a separate tab

Test name	Executions per second
localUndefinedFunc	9850328.0 Ops/sec
wrapped localUndefinedFunc	9724012.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview**

The provided JSON represents a JavaScript benchmark test case on the website MeasureThat.net. The test compares the performance of two approaches: calling a function directly and wrapping it in parentheses.

**Benchmark Definition**

The benchmark definition is a JavaScript function that demonstrates the difference between two approaches:

1. `localUndefinedFunc()`: This function returns an undefined value.
2. `(localUndefinedFunc())`: Wrapping the function call in parentheses does not change its behavior, but it can affect performance due to differences in how the browser evaluates and optimizes this expression.

**Options Compared**

The benchmark compares two options:

1. `localUndefinedFunc()`: This option calls the function directly.
2. `(localUndefinedFunc())`: This option wraps the function call in parentheses.

**Pros and Cons of Each Approach**

* **Direct Call (`localUndefinedFunc()`)**:
	+ Pros: Simple, straightforward approach.
	+ Cons: May not be optimized by the browser due to its lack of syntactic complexity.
* **Wrapped Call (`(localUndefinedFunc())`)**:
	+ Pros: May be optimized by the browser as it resembles a valid expression with parentheses around an argument.
	+ Cons: Requires parentheses, which can increase parsing time and lead to potential errors.

**Library Usage**

None mentioned in the benchmark definition.

**Special JavaScript Features or Syntax**

The test uses a feature called **Immediately Invoked Function Expression (IIFE)**:

`var localUndefinedFunc = (function() { ... }());`

This syntax is used to create a new function scope and return an undefined value. The IIFE is not explicitly necessary in this example, but it's often used for similar use cases.

**Other Considerations**

* **Function Call Optimization**: Modern browsers optimize function calls by reusing existing function objects whenever possible. However, this optimization may not always apply to expressions with parentheses.
* **Parsing Time**: Wrapping a function call in parentheses can increase parsing time due to the additional parsing step required to evaluate the expression.

**Alternatives**

Other approaches could be used to test similar scenarios:

* Using `this` instead of an argument to create a new scope (e.g., `var localUndefinedFunc = function() { return this; }();`)
* Using a closure to create a new scope (e.g., `var localUndefinedFunc = (function() { var notDefinedAgain = undefined; return function() { return notDefinedAgain; }; }());`)
* Using a different data structure, such as an object or array, to store and retrieve the undefined value.

However, these alternatives may change the behavior of the test case and might not be directly comparable to the original benchmark.

Related benchmarks:

Return true vs empty body (version: 0)

Comparing performance of: localUndefinedFunc vs wrapped localUndefinedFunc

Created: 8 years ago by: Guest

Jump to the latest result

localUndefinedFunc

wrapped localUndefinedFunc

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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