var a = [ "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello" ]
var b = [ "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello" ]
var other = a.concat(b)
var a = [ "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello" ]
var b = [ "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello" ]
a.splice(0, a.length, b);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
immutable with concat | |
direct mutation with splice + spread |
Test name | Executions per second |
---|---|
immutable with concat | 13337671.0 Ops/sec |
direct mutation with splice + spread | 11961159.0 Ops/sec |
Let's dive into the benchmark.
What is being tested?
The provided JSON represents two test cases for measuring the performance of joining two arrays in JavaScript: Array.prototype.concat
and splice
. The test cases are designed to compare the execution speed of these two approaches.
Options compared:
concat()
method to create a new array by copying elements from one or more source arrays.splice()
method to modify the existing array and then spreads the elements of another array into the modified array.Pros and Cons:
Library:
None is explicitly mentioned in the provided JSON. However, it's worth noting that Array.prototype.concat()
and Array.prototype.splice()
are native JavaScript methods, so no additional libraries are required.
Special JS feature or syntax:
There are none mentioned in this specific benchmark. The test cases use standard JavaScript features and syntax.
Other alternatives:
Array.prototype.push()
: This method can be used to add elements to the end of an array, but it's not as efficient as concat()
for large arrays.Array.prototype.set()
: This method is available in older browsers (prior to Chrome 64) and allows setting multiple values at once, but it's not supported in modern JavaScript.Benchmark preparation code:
The provided JSON does not include any script preparation code, which means that the benchmark is designed to run on a clean slate, with no additional setup or dependencies required.