var arr1 = ["a", "b", "c", "d"];
var result = [ ["x", "y", "z"], arr1];
var result = arr1.unshift("x", "y", "z");
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
SPREAD | |
UNSHIFT |
Test name | Executions per second |
---|---|
SPREAD | 8856003.0 Ops/sec |
UNSHIFT | 7903.5 Ops/sec |
Let's break down the provided JSON and explain what's being tested, compared options, pros and cons, library usage, special JavaScript features or syntax, and other considerations.
Benchmark Definition
The benchmark is defined as a simple "speed test" with two individual test cases: SPREAD
and UNSHIFT
.
Script Preparation Code
The script preparation code is the same for both test cases:
var arr1 = [\"a\", \"b\", \"c\", \"d\];
This creates an array arr1
containing four string elements.
Html Preparation Code
The html preparation code is null, which means that no HTML content is prepared before running the benchmark. This might be useful for comparing the performance of different JavaScript engines or browsers in a sandboxed environment.
Test Cases
There are two test cases:
Benchmark Definition:
var result = [...[\"x\", \"y\", \"z\"], ...arr1];
This test case creates an array result
by spreading the elements of another array (arr1
) into a new array ([[\"x\", \"y\", \"z\"]]
). The spread operator is used to concatenate the two arrays.
Benchmark Definition:
var result = arr1.unshift(\"x\", \"y\", \"z\");
This test case creates an array result
by unshifting three new elements ("x"
, "y"
, and "z"
) onto the beginning of the original array arr1
.
Options Compared
The two test cases compare two different approaches to manipulate arrays in JavaScript:
...
) to concatenate arrays.Pros and Cons
Pros:
Cons:
Pros:
Cons:
unshift
(most modern browsers do)Library Usage
There is no explicit library usage mentioned in this benchmark. However, some JavaScript engines might use additional libraries or frameworks for their implementation.
Special JavaScript Features or Syntax
The spread operator (...
) and the unshift
method are special features of JavaScript that allow for concise array manipulation. These features were introduced in ECMAScript 2015 (ES6) as part of the new standard.
Other Considerations
var
declarations and no object-oriented programming syntax suggests that this benchmark is intended to test the performance of basic JavaScript operations, rather than more complex scenarios.Alternatives
There are other alternatives for testing JavaScript performance: