const firstObject = { sampleData: 'Hello world', moreData: 'foo bar', evenMoreData: 'overridethis' }
const finalObject = {
firstObject,
evenMoreData: 'test'
};
const firstObject = { sampleData: 'Hello world', moreData: 'foo bar', evenMoreData: 'overridethis' }
const finalObject = Object.assign(firstObject, {evenMoreData: 'test'});
const firstObject = { sampleData: 'Hello world', moreData: 'foo bar', evenMoreData: 'overridethis' }
const finalObject = {
sampleData: firstObject.sampleData,
moreData: firstObject.firstObject,
evenMoreData: 'test'
};
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Using the spread operator | |
Using Object.assign | |
New object |
Test name | Executions per second |
---|---|
Using the spread operator | 13171136.0 Ops/sec |
Using Object.assign | 18790070.0 Ops/sec |
New object | 1294828288.0 Ops/sec |
Let's break down what's being tested in the provided JSON benchmark.
The benchmark is comparing three different approaches to merge objects in JavaScript:
...
): This approach uses the spread operator to create a new object and then merges the firstObject
with it, assigning a new value to evenMoreData
.Object.assign()
: This approach uses the Object.assign()
method to merge two objects and assign the result back to finalObject
.new Object()
): This approach creates a new object using the new Object()
constructor, copies properties from firstObject
, and then assigns a new value to evenMoreData
.Now, let's discuss the pros and cons of each approach:
Spread Operator (...
)
Pros:
Cons:
Object.assign()
Pros:
Cons:
New Object Creation (new Object()
)
Pros:
Cons:
Object.assign()
due to the overhead of creating an intermediate objectThe library used in this benchmark is not explicitly mentioned. However, both Object.assign()
and the spread operator rely on the underlying JavaScript engine's functionality.
There are other alternatives for merging objects in JavaScript, such as using a library like Lodash or Immutable.js, which provide more functional programming-style APIs for working with data structures. Additionally, modern JavaScript engines also provide built-in methods like Object.create()
and Object.assign()
, making it easier to work with objects.
Other special JS features or syntax that might be used in benchmarking include:
However, without more context or explicit mentions of these features, they are not relevant to the explanation provided.