<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
var MyObject = {
description: 'a',
myNumber: 123456789,
myBoolean: true,
};
var myCopy = null;
myCopy = _.cloneDeep(MyObject);
myCopy = _.clone(MyObject);
myCopy = {MyObject};
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Lodash cloneDeep | |
Lodash clone | |
Spread operator |
Test name | Executions per second |
---|---|
Lodash cloneDeep | 1327314.2 Ops/sec |
Lodash clone | 1672655.5 Ops/sec |
Spread operator | 5995431.0 Ops/sec |
Let's dive into the world of JavaScript microbenchmarks!
Benchmark Definition JSON
The provided JSON represents a benchmark test case that compares three different methods for creating a copy of an object in JavaScript: _.cloneDeep
from Lodash, _.clone
, and the spread operator (...
). The benchmark aims to measure which method is the fastest.
Script Preparation Code
The script preparation code creates a sample object MyObject
with properties description
, myNumber
, and myBoolean
. This object will be used as the source of truth for creating copies.
var MyObject = {
description: 'a',
myNumber: 123456789,
myBoolean: true
};
var myCopy = null;
Html Preparation Code
The HTML preparation code includes a reference to the Lodash library, which will be used in the benchmark tests.
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
Individual Test Cases
There are three test cases:
cloneDeep
function to create a deep copy of MyObject
.clone
function to create a shallow copy of MyObject
....
) to create a new object with the same properties as MyObject
.Library: Lodash
Lodash is a popular JavaScript utility library that provides a wide range of functions for working with arrays, objects, and more. The cloneDeep
and clone
functions are used in this benchmark to create copies of objects.
The cloneDeep
function creates a deep copy of an object, meaning it recursively clones all nested properties. This is useful when you need to preserve the entire structure of an object.
The clone
function creates a shallow copy of an object, meaning it only copies the top-level properties and does not recurse into nested objects. This can be faster than cloneDeep
, but may not be suitable for all use cases.
Special JS Feature: Rest Operator (Spread Operator)
The spread operator (...
) is a modern JavaScript feature introduced in ECMAScript 2015. It allows you to create a new object with the same properties as an existing object, without modifying the original.
In this benchmark, the spread operator is used to create a copy of MyObject
. This approach can be fast and memory-efficient, but may not preserve the entire structure of the object if it contains nested objects or complex data structures.
Pros and Cons
Here's a brief summary of each approach:
Lodash cloneDeep: Pros:
Cons:
Lodash clone: Pros:
cloneDeep
due to shallow copying.Cons:
Spread operator: Pros:
Cons:
Other Alternatives
There are several other approaches to creating copies of objects in JavaScript, including:
Object.assign()
: This method creates a shallow copy of an object by assigning the values from another object to new properties.JSON.parse(JSON.stringify(obj))
: This approach creates a deep copy of an object by serializing it as JSON and then parsing it back into an object.Array.prototype.slice.call(obj)
: This approach creates a shallow copy of an array-like object.Each approach has its own trade-offs, and the choice ultimately depends on the specific use case and requirements.