Benchmark: negate - MeasureThat.net

Script Preparation code:

var items = ['', null, undefined, 0, true, false, 1, 'test', NaN, {}]

Tests:

bang
var result = items.filter(item => !!item);
boolean
var result = items.filter(item => Boolean(item));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
bang
boolean

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):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The `MeasureThat.net` website provides a platform for users to create and run JavaScript microbenchmarks. The provided benchmark is designed to test two different approaches to negation in the `filter()` method of an array.

**Script Preparation Code**

The script preparation code defines an array `items` containing various types of values: empty string, null, undefined, 0, truthy value (1), falsy value (false), and NaN (Not a Number).

```javascript
var items = ['', null, undefined, 0, true, false, 1, 'test', NaN, {}];
```

**Benchmark Definition**

The benchmark definition consists of two test cases:

1. `bang`: This test case uses the logical AND operator (`!!`) to negate the values in the array. The `!!` operator converts a value to its Boolean equivalent.
```javascript
var result = items.filter(item => !!item);
```

2. `boolean`: This test case uses the `Boolean()` function to explicitly convert each value to its Boolean equivalent before filtering the array.
```javascript
var result = items.filter(item => Boolean(item));
```

**Comparison of Options**

The two approaches have different pros and cons:

* `bang` (logical AND operator):
	+ Pros:
		- More concise and readable syntax.
		- Works with all types of values, including NaN and objects.
	+ Cons:
		- May be slower due to the additional overhead of the logical AND operation.
* `boolean`: (using `Boolean()` function)
	+ Pros:
		- Can be faster for some cases, since it only converts the value once.
	+ Cons:
		- Less concise and less readable syntax.
		- Does not work with NaN values.

**Library Considerations**

In this benchmark, there are no external libraries being used. The `filter()` method is a native JavaScript array method, and the `Boolean()` function is also part of the standard library.

**Special JS Feature or Syntax**

There is one special feature used in this benchmark: the logical AND operator (`!!`). This operator is not specific to any particular implementation, but it can be a point of contention between vendors. The Chrome browser in the provided benchmark result uses the `!!` operator for negation.

**Alternatives**

If you want to test alternative approaches to negation in JavaScript arrays, here are some options:

* Using `Array.prototype.map()` and negating the results: `items.map(item => !item)`
* Using `Array.prototype.every()` with a callback function that returns a falsy value for each item: `items.every(item => !(item || true))`
* Using a library like Lodash, which provides a `filterBy()` method that can be used to negate values.

Keep in mind that these alternatives may have different performance characteristics and trade-offs compared to the original approach.

Related benchmarks:

negate (version: 0)

test negation

Comparing performance of: bang vs boolean

Created: 5 years ago by: Guest

Jump to the latest result

bang

boolean

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):