Benchmark: JS Array Clearing3

Script Preparation code:

var a = [];
for (var i=0; i < 10000000;i++){
  a.push("item"+i + Math.random());
}

function remove(arr) {
  while(arr.length) {
    arr.shift(); 
  }
}



function remove2(arr) {
  while(arr.length) {
    arr.pop(); 
  }
}

Tests:

Length = 0
a.length = 0;
Splice
a.splice(0, a.length-1);
Shift
remove(a);
Pop
remove2(a);
array = []
a = [];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Length = 0
Splice
Shift
Pop
array = []

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.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case, specifically measuring the performance of array clearing and manipulation techniques. The benchmark is designed to evaluate which approach is faster: using `shift()` or `pop()` methods on an array.

**Tested Options**

Two primary options are being compared:

1. **`array = []`**: This option creates a new empty array by reassigning the variable `a`.
2. **Array length manipulation**: Three techniques are used to clear the array:
	* **`remove(a)`**: Calls a custom function `remove()` that shifts all elements from the beginning of the array.
	* **`remove2(a)`**: Calls another custom function `remove2()` that pops all elements from the end of the array.
	* **`a.splice(0, a.length-1)`**: Uses the `splice()` method to remove all elements from the beginning of the array.

**Pros and Cons**

Each approach has its advantages:

1. **`array = []`**:
	* Pros: Creates a new empty array without modifying the original data.
	* Cons: May incur overhead due to reassigning the variable.
2. **`remove(a)`**:
	* Pros: Shifting elements is often faster than popping them, as it doesn't require searching for an index.
	* Cons: Reverses the order of elements in the array.
3. **`remove2(a)`**:
	* Pros: Popping elements can be faster if the array is not already sorted or reversed.
	* Cons: Requires iterating through the entire array to find the correct index.
4. **`a.splice(0, a.length-1)`**:
	* Pros: Directly removes elements from the beginning of the array without iteration.
	* Cons: May be slower due to the overhead of creating an empty slice.

**Library Usage**

None of the test cases use external libraries.

**Special JavaScript Features/Syntax**

None are mentioned, so we won't delve into any specific language features or syntax.

**Other Alternatives**

Other approaches for clearing arrays could include:

* Using `Array.prototype.fill()` with a new value
* Creating a new array using `Array.from()` and assigning it to the original variable
* Using a different data structure, like a linked list

However, these alternatives are not being tested in this specific benchmark.

**Benchmark Preparation Code**

The provided preparation code sets up an initial array `a` with 10 million elements, each containing a random string. The script then defines two custom functions: `remove()` and `remove2()`, which shift or pop all elements from the array, respectively.

**Individual Test Cases**

Each test case has a single benchmark definition:

1. **`array = []`**: Creates an empty new array by reassigning the variable `a`.
2. **Length = 0**: Checks if the array length is zero after clearing it.
3. **Splice**: Verifies that the array was cleared using `splice(0, a.length-1)`.
4. **Shift**: Confirms that the array was shifted using `remove(a)` function.
5. **Pop**: Validates that the array was popped using `remove2(a)` function.
6. **array = []`: Another instance of creating an empty new array.

These test cases help ensure that the benchmark is measuring the correct performance characteristics for each approach.

Related benchmarks:

JS Array Clearing3 (version: 2)

Comparing performance of: Length = 0 vs Splice vs Shift vs Pop vs array = []

Created: 4 years ago by: Registered User

Jump to the latest result

Length = 0

Splice

Shift

Pop

array = []

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):