var array = Array.from({ length: 100 }).map((val, i) => i);
var newArray = array.slice(0, 0, 99);
var newArray = [99, array];
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Splice | |
Spread |
Test name | Executions per second |
---|---|
Splice | 11036329.0 Ops/sec |
Spread | 1864112.6 Ops/sec |
Let's break down the provided benchmark and its options.
Benchmark Overview
The test case measures the performance of two approaches to insert an element at the beginning of an array: splice
(Splice) and spread operator (...
) with array destructuring. The arrays are created using Array.from()
and have a length of 100 elements.
Options Compared
There are two options being compared:
...
) and then uses array destructuring to include the desired element at the beginning.Pros and Cons of Each Approach
Pros:
Cons:
Pros:
splice
for large arrays since it avoids the overhead of re-inserting elementsCons:
Library/Functionality Used
None, as both options are built-in JavaScript methods.
Special JS Feature/Syntax
The ...
spread operator is a relatively recent addition to JavaScript (introduced in ECMAScript 2015). It allows for creating a new array by spreading elements from an existing array or object. Array destructuring is also a feature introduced in ECMAScript 2010, which enables extracting values from arrays into separate variables.
Other Alternatives
For large arrays or when performance is critical, other methods like concat()
or libraries like Lodash's insertAt
function might be considered as alternatives. However, these approaches may have different trade-offs and use cases compared to the spread operator and splice
.
In summary, the benchmark compares two efficient ways to insert an element at the beginning of an array in JavaScript: splice
and spread operator with array destructuring. The choice between them depends on the specific requirements, such as preserving the original array or considering performance for large arrays.