Benchmark: event emit - MeasureThat.net

Script Preparation code:

var listeners = [
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  () => {},
  ];

var args = [];

Tests:

orig
for (let i = 0, { length } = listeners; i < listeners; ++i) { const result = listeners[i].apply(this, args); // We check if result is undefined first because that // is the most common case so we do not pay any perf // penalty. // This code is duplicated because extracting it away // would make it non-inlineable. if (result !== undefined && result !== null) { } }
sniff
for (let i = 0, { length } = listeners; i < length; ++i) { const listener = listeners[i]; const result = listener(); // We check if result is undefined first because that // is the most common case so we do not pay any perf // penalty. // This code is duplicated because extracting it away // would make it non-inlineable. if (result !== undefined && result !== null) { } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
orig
sniff

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
orig	975515.4 Ops/sec
sniff	631464.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript microbenchmarks can be fascinating, and Measurathat.net is an excellent resource for doing so.

**Benchmark Definition**

The provided JSON represents a benchmark definition for testing event emission in JavaScript. The benchmark consists of two main components:

1. **Script Preparation Code**: This code initializes an array `listeners` containing 12 anonymous functions (i.e., callbacks) with no arguments and no returns. This setup is used to test the execution of individual listeners in a loop.
2. **Html Preparation Code**: There is no HTML preparation code provided, which implies that this benchmark might be running in a headless or server-side environment.

**Options Compared**

In this benchmark, two options are compared:

1. **Option 1: Original Looping Structure**
```javascript
for (let i = 0, { length } = listeners; i < listeners; ++i) {
  const result = listeners[i].apply(this, args);
  // ...
}
```
This implementation uses a traditional `for` loop with the length of the `listeners` array as its condition.

2. **Option 2: Looped Through Array Length**
```javascript
for (let i = 0, { length } = listeners; i < length; ++i) {
  const listener = listeners[i];
  const result = listener();
  // ...
}
```
This implementation uses a `for` loop with the array length as its condition and then accesses individual elements of the array using indexing.

**Pros and Cons**

Both options have their advantages and disadvantages:

**Option 1: Original Looping Structure**

Pros:

* More readable code, as it explicitly states the loop's condition.
* May be more intuitive for developers familiar with traditional `for` loops.

Cons:

* The length property is accessed multiple times, which can lead to slower performance due to unnecessary object lookups.

**Option 2: Looped Through Array Length**

Pros:

* Only accesses the array length once, reducing overhead.

Cons:

* Requires explicit indexing of elements within the loop, making the code slightly less readable.
* May require additional variables or functions for element access.

**Considerations**

In general, the choice between these two options depends on performance considerations and personal coding style. If readability is a priority, Option 1 might be preferred. However, if optimization is crucial, Option 2 could be a better choice due to its reduced overhead from accessing the array length multiple times.

**Library Usage (None)**

There are no libraries used in this benchmark definition.

**Special JS Features (None)**

Since there are no special JavaScript features or syntax mentioned in the provided code, it's unlikely that any advanced features like async/await, `let` declarations, or classes would affect the performance difference between these two options.

**Alternatives**

Other alternatives to compare when testing event emission include:

* Using a different array data structure (e.g., linked list) instead of an array.
* Adding additional listeners or modifying existing ones to increase complexity.
* Utilizing event emitters with higher-level APIs, like `emitter.emit()`.
* Implementing asynchronous event handling using promises or async/await.

These variations can help ensure that the benchmark accurately reflects real-world scenarios and challenges.

Related benchmarks:

event emit (version: 1)

Comparing performance of: orig vs sniff

Created: one year ago by: Registered User

Jump to the latest result

orig

sniff

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):