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spread vs concat vs unshift vs slice.unshift
(version: 0)
spread vs concat vs unshift vs slice.unshift
Comparing performance of:
arrayUnshift123C vs arrayConcat123C vs arraySpread123C vs arraySliceUnshift123C
Created:
2 years ago
by:
Guest
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Script Preparation code:
var array = [1,2,3];
Tests:
arrayUnshift123C
array.unshift(0);
arrayConcat123C
array = array.concat([0])
arraySpread123C
array = [0, ...array]
arraySliceUnshift123C
array.slice().unshift(0);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (4)
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Test case name
Result
arrayUnshift123C
arrayConcat123C
arraySpread123C
arraySliceUnshift123C
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Overview** The provided JSON represents a benchmarking test case on MeasureThat.net, which compares the performance of different array manipulation methods in JavaScript: `unshift`, `concat`, `spread` (via rest parameter syntax), and `slice.unshift`. **Benchmark Definition** The benchmark definition is represented by two parts: 1. **Script Preparation Code**: The code that initializes an array with three elements (`var array = [1,2,3];`) before each test case. 2. **Html Preparation Code**: An empty string, indicating that no additional HTML preparation is required. **Individual Test Cases** Each test case represents a specific scenario: 1. `array.unshift(0);`: Pushes the element 0 onto the end of the array using `unshift`. 2. `array = array.concat([0])`: Creates a new array by concatenating the original array with an array containing the element 0. 3. `array = [0, ...array]`: Spreads the elements of the original array after the initial element 0 using rest parameter syntax. 4. `array.slice().unshift(0)`: Slices the original array to create a new slice, and then uses `unshift` on that slice. **Options Compared** The benchmark compares the performance of four different methods: 1. `unshift` 2. `concat` 3. `spread` (via rest parameter syntax) 4. `slice.unshift` **Pros and Cons of Each Approach** Here's a brief overview of each approach: 1. **`unshift`**: This method has an average time complexity of O(n), making it inefficient for large arrays. 2. **`concat`**: This method also has an average time complexity of O(n) but is slightly faster than `unshift` due to its optimized implementation. 3. **`spread` (rest parameter syntax)**: This approach uses a rest parameter (`...array`) to spread the elements, which is more efficient than concatenating or using `slice.unshift`. 4. **`slice.unshift`**: This method slices the original array and then uses `unshift`, which can be slower than the other methods due to the additional operation. **Library and Special JS Features** None of the provided test cases use any external libraries. However, they do utilize special JavaScript features: 1. Rest parameter syntax (`...array`) is used in the `array = [0, ...array]` test case. 2. The `concat` method uses a non-standard implementation on some browsers. **Other Alternatives** Some alternative methods could be explored for comparison, such as: 1. Using `splice` instead of `unshift` 2. Utilizing `Array.prototype.push()` and `Array.prototype.length` 3. Implementing custom array manipulation functions Keep in mind that the choice of alternative methods depends on the specific requirements of the benchmark and the performance characteristics of each method. **Interpretation of Benchmark Results** The provided results indicate that: 1. The `spread` (rest parameter syntax) approach is the fastest, followed closely by `concat`. 2. `unshift` is slower than both `concat` and `spread`. 3. `slice.unshift` is the slowest due to its additional operation. This benchmark provides valuable insights into the performance characteristics of different array manipulation methods in JavaScript.
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