Benchmark: Array filter falsy

Script Preparation code:

var test = [];
for (let step = 0; step < 999999; step++) {
  test.push(Boolean(step%2));
}

Tests:

e => e filter
var res1 = test.filter(e => e);
Boolean filter
var res2 = test.filter(Boolean);
function(item) {return item}
var res3 = test.filter(function(e) {return e});
function(item) {return Boolean(item)}
var res4 = test.filter(function(e) {return Boolean(e)});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
e => e filter
Boolean filter
function(item) {return item}
function(item) {return Boolean(item)}

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain the JavaScript microbenchmark you provided.

**Benchmark Definition**

The benchmark measures how fast different approaches can filter out falsy values from an array of numbers.

**Options Compared**

There are four options compared in this benchmark:

1. **e => e filter**: This approach uses a function expression with an arrow function syntax, where `e` is the current element being processed.
2. **Boolean filter**: This approach uses the `Boolean` function to convert each element to a boolean value before filtering.
3. **function(item) {return item}`: This approach defines a separate function that takes an element as input and returns it if true, or falsy otherwise.
4. **function(item) {return Boolean(item)}**: This approach combines the previous one with the `Boolean` function to convert each element to a boolean value before filtering.

**Pros and Cons of Each Approach**

Here are some pros and cons of each approach:

1. **e => e filter**:
	* Pros: concise, efficient, and idiomatic JavaScript syntax.
	* Cons: may not be as readable for complex filtering tasks.
2. **Boolean filter**:
	* Pros: simple, easy to understand, and avoids function declarations.
	* Cons: requires the `Boolean` function, which can lead to unnecessary function calls.
3. **function(item) {return item}`:
	* Pros: explicit control over filtering logic, easy to read and maintain.
	* Cons: more verbose than arrow functions or boolean filters.
4. **function(item) {return Boolean(item)}**:
	* Pros: combines the benefits of previous approaches (easier to read than a separate function but still avoids unnecessary `Boolean` calls).
	* Cons: still uses an extra function declaration, which may be unnecessary.

**Library and Special Features**

There are no libraries mentioned in the benchmark definition or test cases. However, it's worth noting that some JavaScript engines may optimize certain features or syntax (like arrow functions) at the bytecode level, making them more efficient than others.

**Other Considerations**

The benchmark only tests filtering out falsy values from an array of numbers. Depending on the use case, you might want to consider additional filtering options or edge cases.

**Alternative Approaches**

Some alternative approaches could include:

* Using `Array.prototype.filter()` with a callback function that directly returns `true` or `false`.
* Implementing custom filtering logic using bitwise operations (e.g., checking for zero value).
* Comparing the performance of different JavaScript engines or versions.
* Adding more test cases to cover additional filtering scenarios.

Keep in mind that this benchmark is specifically designed for comparing these four approaches, and exploring alternative methods might not be as relevant.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0

Browser/OS: Firefox 69 on Windows

View result in a separate tab

Test name	Executions per second
e => e filter	162.0 Ops/sec
Boolean filter	156.0 Ops/sec
function(item) {return item}	130.9 Ops/sec
function(item) {return Boolean(item)}	48.1 Ops/sec

Related benchmarks:

Array filter falsy (version: 0)

Comparing performance of: e => e filter vs Boolean filter vs function(item) {return item} vs function(item) {return Boolean(item)}

Created: 5 years ago by: Guest

Jump to the latest result

e => e filter

Boolean filter

function(item) {return item}

function(item) {return Boolean(item)}

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):