Benchmark: JS unshift vs slice with modifications

Script Preparation code:

var data1 = [];
for(i=0; i<10000; i++){data1.push(i);}
var data2 = [];
for(i=0; i<10000; i++){data2.push(i);}

Tests:

Unshift with find
const rest = data1.filter(item => item !== 600); rest.unshift(data1.find(item => item.type == 600)); return rest;
Slice with findIndex
const cautelarPosition = data2.findIndex(item => item.type == 500); data2.splice(0, 0, data2.splice(cautelarPosition, 1)[0]); return data2;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Unshift with find
Slice with findIndex

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the benchmark definition and test cases.

**Benchmark Definition:**

The benchmark measures two approaches to modify an array in JavaScript:

1. **Unshift with `find`**: This approach uses the `unshift()` method to add an element to the beginning of the array, while also using the `find()` method to find the desired element.
2. **Slice with `findIndex`**: This approach uses the `slice()` method to remove elements from the end of the array and then adds the desired element at the beginning using `splice()`.

**Options being compared:**

* `unshift()` vs `slice()`: The benchmark compares the performance of using `unshift()` to add an element to the beginning of the array versus using `slice()` to remove elements from the end.
* `find()` vs `findIndex()`: The benchmark also compares the performance of using `find()` to find a specific element within the array versus using `findIndex()`.

**Pros and Cons:**

1. **Unshift with `find`**:
	* Pros: This approach is simple and easy to understand, as it uses standard JavaScript methods.
	* Cons: It may be slower than other approaches because `unshift()` needs to iterate through the entire array to find the desired element.
2. **Slice with `findIndex`**:
	* Pros: This approach can be faster than `unshift()`, especially when dealing with large arrays, since it only iterates through a portion of the array using `slice()`.
	* Cons: It requires more complex logic and may be less readable due to the use of `splice()`.

**Libraries and special features used:**

* None of the benchmark definitions explicitly mention any libraries being used.
* However, the test cases do use JavaScript features:
	+ `filter()`: Used in both test cases to remove unwanted elements from the array.
	+ `find()`: Used in the first test case to find a specific element within the array.
	+ `findIndex()`: Used in the second test case to find the index of a specific element within the array.
	+ `splice()`: Used in both test cases to add or remove elements from the array.

**Other alternatives:**

Some alternative approaches that could be used to modify an array in JavaScript include:

1. Using `concat()` to create a new array instead of modifying the original one.
2. Using `push()` and `pop()` to add or remove elements from the end of the array.
3. Using `map()` and `forEach()` to transform or iterate over the array.

It's worth noting that the choice of approach depends on the specific requirements and constraints of the use case, such as performance, readability, and maintainability.

**Benchmark result:**

The benchmark results show that the "Slice with findIndex" approach performed better than the "Unshift with find" approach. This could be due to the optimized implementation of `slice()` in modern JavaScript engines or the simplicity of the logic used in the second test case.

Related benchmarks:

JS unshift vs slice with modifications (version: 0)

Comparing performance of: Unshift with find vs Slice with findIndex

Created: 4 years ago by: Guest

Jump to the latest result

Unshift with find

Slice with findIndex

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):