var array = Array(100).fill(1);
let i = 10000;
while(i>0) {
const t1 = array.splice()
i--;
}
let i = 10000;
while(i>0) {
const t1 = [array];
i--;
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
splice | |
deconstruct |
Test name | Executions per second |
---|---|
splice | 636.7 Ops/sec |
deconstruct | 377.5 Ops/sec |
I'll break down the benchmark and explain what's being tested, compared options, pros and cons, library usage, special JS features or syntax, and other considerations.
Benchmark Definition
The benchmark is titled "Splice vs deconstruction based copy". It tests two approaches to creating a shallow copy of an array: using Array.prototype.splice()
and using the spread operator (...
).
Script Preparation Code
var array = Array(100).fill(1);
This code creates an array with 100 elements, all initialized to 1.
Html Preparation Code
There is no HTML preparation code provided, which suggests that this benchmark only tests JavaScript performance and does not consider DOM-related overhead.
Individual Test Cases
The benchmark consists of two test cases:
let i = 10000;
while(i>0) {
const t1 = array.splice();
i--;
}
This code uses Array.prototype.splice()
to remove elements from the original array. The variable t1
will be assigned the removed element, but it's not clear what value this variable holds (it might be undefined
, depending on how many elements are removed).
let i = 10000;
while(i>0) {
const t1 = [...array];
i--;
}
This code uses the spread operator (...
) to create a shallow copy of the original array. The variable t1
is assigned a reference to the copied array.
Comparison
The benchmark tests which approach (splice vs deconstruction) results in faster execution.
Options Compared
Array.prototype.splice()
to remove elements from an array....
) to create a shallow copy of an array.Pros and Cons
Library Usage
There is no library usage in this benchmark. Both Array.prototype.splice()
and the spread operator are built-in JavaScript features.
Special JS Feature or Syntax
None mentioned explicitly, but it's worth noting that the spread operator (...
) was introduced in ECMAScript 2015 (ES6). If you're using an older version of JavaScript, this benchmark might not be relevant to your use case.
Other Considerations
The benchmark only tests JavaScript performance and does not consider other factors like memory usage or garbage collection. Additionally, the test cases do not account for edge cases, such as empty arrays or arrays with a single element.
Alternatives
If you're interested in comparing other array manipulation approaches, you could explore:
Array.prototype.slice()
Array.prototype.map()
and Array.prototype.forEach()
Buffer
APIs (e.g., Buffer.from()
, Buffer.concat()
)