Benchmark: extend vs cloneDeep vs JSON.*

HTML Preparation code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/2.4.1/lodash.min.js"></script>

Script Preparation code:

var myObj = {
    "name":"John",
    "age":30,
    "cars": {
        "car1":"Ford",
        "car2":"BMW",
        "car3":"Fiat"
    }
 }

Tests:

extend
let a = Object.extend({}, myObj)
cloneDeep
let a = _.cloneDeep(myObj)
JSON.*
let a = JSON.parse(JSON.stringify(myObj))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
extend
cloneDeep
JSON.*

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36

Browser/OS: Chrome 66 on Windows

View result in a separate tab

Test name	Executions per second
extend	0.0 Ops/sec
cloneDeep	392393.0 Ops/sec
JSON.*	267785.8 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**What is being tested?**

The benchmark measures the performance difference between three approaches to create a deep copy of an object:

1. `Object.extend()`: This method creates a new object and copies all properties from the original object using the `extend` method.
2. `_.cloneDeep()` (using Lodash library): This method creates a deep clone of the original object, which means it recursively copies all nested objects and arrays.
3. `JSON.parse(JSON.stringify())`: This method uses JSON serialization to create a new object with the same structure as the original object.

**Options compared:**

The benchmark compares these three approaches to create a deep copy of an object, specifically in this case, the `myObj` object provided in the script preparation code.

**Pros and cons of each approach:**

1. **Object.extend()**:
	* Pros: Simple and easy to implement.
	* Cons: Can be slow and inefficient, especially for large objects or complex structures.
	* Additional consideration: This method modifies the original object by creating a new one with updated references.
2. **_.cloneDeep()` (using Lodash library):
	* Pros: Fast and efficient, provides a deep clone of the original object.
	* Cons: Requires an external library (Lodash) to be included in the script.
	* Additional consideration: This method is more expensive than `Object.extend()`, but it's worth it for its performance benefits.
3. **JSON.parse(JSON.stringify())**:
	* Pros: Fast and efficient, provides a deep clone of the original object.
	* Cons: Can fail if the original object contains circular references or non-serializable properties (e.g., functions).
	* Additional consideration: This method is more fragile than `_.cloneDeep()` since it's prone to errors due to its reliance on JSON serialization.

**Special JS feature/syntax:**

None of the provided benchmark options use any special JavaScript features or syntax. They all rely on standard language constructs and libraries (Lodash).

**Other alternatives:**

If you need more advanced deep copying capabilities, you might consider using:

1. `Object.assign()`: While not a built-in method for deep copying, you can create a recursive function that uses `Object.assign()` to copy objects.
2. `es6 Object.assign() with spread operator (`): If you're targeting modern browsers or environments (ECMAScript 2017+), you can use the spread operator (`{ ... }`) to create a shallow copy of an object, which can be used as a starting point for deep copying.
3. Custom library: There are other libraries available that provide more advanced deep copying capabilities, such as `lodash-es` or `copy-deep`.

Keep in mind that the choice of approach depends on your specific use case and requirements.

Related benchmarks:

extend vs cloneDeep vs JSON.* (version: 0)

Comparing performance of: extend vs cloneDeep vs JSON.*

Created: 6 years ago by: Guest

Jump to the latest result

extend

cloneDeep

JSON.*

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):