var baseArray = []for (var i = 0; i < 50; i++) { baseArray.push((Math.floor(Math.random() * Math.floor(1000000))).toString(16)) }var other = baseArray.slice();var other = [ baseArray ]var other = baseArray.slice(0);--enable-precise-memory-info flag.
| Test case name | Result |
|---|---|
| Array.prototype.slice() | |
| spread operator | |
| Array.prototype.slice(0) |
| Test name | Executions per second |
|---|---|
| Array.prototype.slice() | 52263380.0 Ops/sec |
| spread operator | 38926020.0 Ops/sec |
| Array.prototype.slice(0) | 52732644.0 Ops/sec |
Overview
MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark definition, which includes the script preparation code, HTML preparation code (none in this case), and individual test cases.
The benchmark compares three approaches for creating a subset of an array: using Array.prototype.slice(), the spread operator (...), and slice(0).
Options Compared
The three options are compared to determine which approach is most efficient.
Array.prototype.slice(): This method creates a shallow copy of a portion of an array....): This syntax creates a new array by spreading the elements of an existing array.slice(0): This method returns a shallow copy of a portion of an array, starting from index 0.Pros and Cons
Array.prototype.slice():...):slice(), can be slower due to array creation.slice(0):Library and Special JS Features
None of the test cases use any libraries or special JavaScript features beyond standard ES6 syntax.
Other Alternatives
For creating subsets of arrays, there are other alternatives:
Array.prototype.slice() with an offset: Instead of using slice(0), you can use slice(offset) to create a subset starting from a specific index.Array.prototype.splice(): While not exactly the same as creating a subset, splice() allows you to remove and return elements from an array, which can be useful in certain scenarios.In summary, the choice of approach depends on the specific use case and performance requirements. If you need to create a shallow copy of a small array, any of the three options are suitable. For very large arrays, Array.prototype.slice() might be the most efficient option due to its widespread support and optimized implementation.
