Benchmark: bitwise vs string compare

Tests:

bitwise
const a = 63 if (a ^ 1) {}; if (a ^ 2) {}; if (a ^ 4) {}; if (a ^ 8) {}; if (a ^ 16) {}; if (a ^ 32) {};
typeof array
const a = [{type: 'add'}, {type: 'remove'}, {type: 'move'}, {type: 'attribute'}, {type: 'reference'}, {type: 'children'}]; a.forEach(v => { if (v.type === 'add'){}; if (v.type === 'remove'){}; if (v.type === 'move'){}; if (v.type === 'attribute'){}; if (v.type === 'reference'){}; if (v.type === 'children'){}; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
bitwise
typeof array

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Windows

View result in a separate tab

Test name	Executions per second
bitwise	105899952.0 Ops/sec
typeof array	34892064.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark JSON and explore what's being tested, compared, and the pros/cons of each approach.

**Benchmark Definition JSON**

The provided `Benchmark Definition` is empty, which means that the actual benchmarking code is expected to be provided in the `Script Preparation Code` or `Html Preparation Code` fields. However, since these fields are also empty, we'll focus on interpreting the individual test cases.

**Individual Test Cases**

There are two test cases:

1. **"bitwise "**

This test case uses a simple JavaScript expression that compares a value using bitwise XOR (`^`) with different numbers: 1, 2, 4, 8, and 16.

```javascript
const a = 63
if (a ^ 1) {}
if (a ^ 2) {}
if (a ^ 4) {}
if (a ^ 8) {}
if (a ^ 16) {}
```

The purpose of this test is likely to measure the performance difference between using bitwise XOR and comparing values directly. The `bitwise` option in the benchmark suggests that we're interested in seeing how this approach compares to other methods.

**Pros/Cons:**

* **Bitwise XOR:** This method can be faster because it involves a single operation, whereas direct comparisons may involve additional overhead (e.g., conditional branches).
* **Direct comparison:** Directly comparing values using `===` or `!=` might be slower due to the potential for branch prediction errors.

2. **"typeof array"**

This test case uses an example from the MDN documentation, which compares the results of calling `typeof` on a simple array:

```javascript
const a = [{ type: 'add' }, { type: 'remove' }, { type: 'move' }, { type: 'attribute' }, { type: 'reference' }, { type: 'children' }];

a.forEach(v => {
  if (v.type === 'add') {}
  if (v.type === 'remove') {}
  if (v.type === 'move') {}
  if (v.type === 'attribute') {}
  if (v.type === 'reference') {}
  if (v.type === 'children') {}
});
```

The purpose of this test is to measure the performance difference between using `typeof` with different types.

**Pros/Cons:**

* **typeof:** This method returns a string indicating the type of the value, which might be slower due to the potential for array indexing or other overhead.
* **Array iteration:** Directly iterating over the array elements and comparing values may involve additional overhead (e.g., branch prediction errors).

**Library Usage**

There is no explicit library usage mentioned in these test cases. However, the use of `forEach` suggests that the test is checking the performance of using a specific JavaScript feature.

**Special JS Features/Syntax**

The only special syntax used here is `forEach`, which is a built-in method for iterating over arrays and other iterable objects.

**Other Alternatives**

To measure the performance difference between these approaches, you could also consider the following alternatives:

* Use `for` loops instead of `forEach` to iterate over the array elements.
* Compare values using `==` or `===` instead of bitwise XOR.
* Measure the performance of direct comparisons (e.g., using `a === b`) versus indirect comparisons (e.g., using `a ^ 1`).
* Use a different data structure, such as an object with multiple properties, to compare performance.

Keep in mind that these alternatives would likely change the focus or scope of the benchmark, and might not directly compare the same aspects.

Related benchmarks:

bitwise vs string compare (version: 0)

Comparing performance of: bitwise vs typeof array

Created: 2 years ago by: Guest

Jump to the latest result

bitwise

typeof array

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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