var input = [];
for (var i = 0; i < 50000; i++) {
input.push({
id: i,
data: 'something'
})
}
const index = input.findIndex(val => val.id === 999);
input.splice(index, 1, {id: 999, data: 'somethingElse'});
input = {
input,
[999]: {id: 999, data: 'somethingElse'}
}
input[999] = {id: 999, data: 'somethingElse'}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Array splice | |
ES6 Object Spread | |
Object property assign |
Test name | Executions per second |
---|---|
Array splice | 1435029.6 Ops/sec |
ES6 Object Spread | 10134.6 Ops/sec |
Object property assign | 63001104.0 Ops/sec |
Let's break down the provided benchmark and explain what's being tested.
Benchmark Definition
The benchmark is defined by a JSON object that contains the following information:
Name
: The name of the benchmark, which is "Array splice vs object assign".Description
: No description is provided for this benchmark.Script Preparation Code
: A JavaScript code snippet that creates an array with 50,000 objects and assigns an ID to each object. This script is used to prepare the input data for the benchmark.Html Preparation Code
: No HTML preparation code is provided.The purpose of this script is to create a large array of objects that can be used as input for the test cases.
Individual Test Cases
There are three test cases defined, each with its own Benchmark Definition
:
const index = input.findIndex(val => val.id === 999);
input.splice(index, 1, {id: 999, data: 'somethingElse'});
This test case uses the splice()
method to remove an element from the array and replace it with a new object. The findIndex()
method is used to find the index of the element to be removed.
input = { ...input, [999]: {id: 999, data: 'somethingElse'} };
This test case uses the spread operator (...
) to create a new object that includes all properties from the original input
array and adds a new property at index 999.
input[999] = {id: 999, data: 'somethingElse'};
This test case uses direct property assignment to replace an element in the array with a new object.
Library Used
The benchmark does not use any external libraries beyond the built-in JavaScript Array
and Object
prototypes. However, it does use some modern JavaScript features, such as arrow functions (e.g., val => val.id === 999
) and the spread operator (...
).
Special JS Features or Syntax
The benchmark uses several special JavaScript features:
findIndex()
method is used in the Array Splice test case....
) is used in the ES6 Object Spread test case.input[999] = { ... }
) is used in the Object Property Assign test case.Pros and Cons
Here are some pros and cons of each approach:
Other Alternatives
There are several alternative approaches that could be used in this benchmark, such as:
Array.prototype.map()
and Array.prototype.forEach()
JSON.parse(JSON.stringify(input))
and then modifying the resulting objectHowever, these alternatives may not provide significant performance benefits over the existing test cases.