var arr = [10]
arr.unshift(42)
arr.push(42)
arr = [42,arr]
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
.unshift() | |
.push() | |
Spread |
Test name | Executions per second |
---|---|
.unshift() | 442417.3 Ops/sec |
.push() | 25841922.0 Ops/sec |
Spread | 0.2 Ops/sec |
Let's dive into the benchmark and explain what's being tested.
Benchmark Overview
The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net. The test aims to compare the performance of three different approaches: Array.push()
, Array.unshift()
, and using array spread syntax (arr = [42, ...arr]
).
Options Compared
We're comparing the following options:
Array.push()
: This is a simple way to add an element to the end of an array.Array.unshift()
: This method adds an element to the beginning of an array.arr = [42, ...arr]
): This syntax creates a new array by concatenating the original array with a new array containing the specified elements.Pros and Cons
Array.push()
:Array.unshift()
:push()
for small arrays because it doesn't require concatenation. It also avoids unnecessary reallocations when using sparse arrays.push()
.arr = [42, ...arr]
):push()
for large arrays because it avoids the overhead of concatenation operations. It also works with sparse arrays.Library Usage
There is no explicit library usage in this benchmark, but we can infer that the array methods are part of the built-in JavaScript API.
Special JS Features or Syntax
None of the provided test cases use special JavaScript features or syntax. They're straightforward examples of basic array operations.
Other Alternatives
If you were to run a similar benchmark using alternative approaches, some options could include:
Array.prototype.concat()
instead of spread syntax._.uniq
) for array manipulation.For example, if we wanted to compare the performance of different methods for appending elements to an array, our benchmark could look like this:
{
"Name": "Array Append",
"Description": null,
"Script Preparation Code": "var arr = []",
"Html Preparation Code": null,
"Individual test cases": [
{
"Benchmark Definition": "arr.push(42)",
"Test Name": ".push()"
},
{
"Benchmark Definition": "arr.concat([42])",
"Test Name": "concat()"
},
{
"Benchmark Definition": "var newArr = [42]; arr = newArr;",
"Test Name": "custom append"
}
]
}
Keep in mind that the choice of alternative approaches would depend on the specific requirements and constraints of your benchmark.