var array = Array.from({ length: 2000 }).map((val, i) => i);
var newArray = array.splice(0, 0, 99);
var newArray = [99, array];
var newArray = array.unshift(99);
var newArray = array.push(99);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Splice | |
Spread | |
Unshift | |
Push |
Test name | Executions per second |
---|---|
Splice | 6253.2 Ops/sec |
Spread | 201.8 Ops/sec |
Unshift | 681890.8 Ops/sec |
Push | 27800920.0 Ops/sec |
Let's break down the provided benchmark and explain what's being tested.
What is being tested?
The benchmark is testing four different methods to insert an element at the beginning of an array:
Splice
: Using the splice
method with two arguments (index and number of elements to remove).Spread
: Using the spread operator (...
) to create a new array with the original array as its first element.Unshift
: Using the unshift
method to add one or more elements at the beginning of an array.Push
: Using the push
method to add one or more elements at the end of an array.Options compared
The benchmark is comparing the performance of these four methods on a large array (2000 elements) with different types and values of elements.
Pros and Cons of each approach:
splice
or push
.Library used:
None explicitly mentioned. However, the benchmark uses the Array.from()
method to create a large array with 2000 random values, which suggests that modern JavaScript environments support this method.
Special JS feature or syntax:
The benchmark uses the spread operator (...
) in the "Spread" test case, which is a relatively new feature introduced in ECMAScript 2015 (ES6). This syntax allows for concise and expressive array creation.
Other considerations:
Alternatives:
Other methods for inserting elements at the beginning of an array include:
concat()
: This method creates a new array by concatenating two or more arrays. However, it's generally slower and less efficient than the other methods.Array.prototype.concat.call(array, [99])
: This method is similar to concat()
, but uses the call()
method to call the concat()
function on an array with an initial value.Keep in mind that these alternatives might not be as fast or efficient as the benchmark's chosen methods.