Benchmark: Manual clone versus prototype extend

Script Preparation code:

var MergeState = (function () {
        function MergeState() {
            this.writeVersion = 0;
            this.deepInspect = false;
        }
        MergeState.prototype.derive1 = function () {
            var ret = new MergeState();
            ret.writeVersion = this.writeVersion;
            ret.deepInspect = this.deepInspect;
            return ret;
        };
        MergeState.prototype.derive2 = function () {
            var ret = {};
            Object.setPrototypeOf(ret, this);
            return ret;
        };
        return MergeState;
    }());

var base = new MergeState();

Tests:

Manual clone
var der = base.derive1();
Prototype
var der = base.derive2();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Manual clone
Prototype

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Browser/OS: Chrome 53 on Mac OS X 10.10.5

View result in a separate tab

Test name	Executions per second
Manual clone	9802892.0 Ops/sec
Prototype	1620940.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**

The benchmark tests two approaches to cloning an object in JavaScript:

1. **Manual Clone:** This approach creates a new instance of the `MergeState` class using the `new` keyword, just like creating any other object in JavaScript.
2. **Prototype Extend:** This approach uses the `Object.setPrototypeOf()` method to set the prototype of a new object (`ret`) to the current instance (`this`).

**Options Compared:**

The benchmark compares the performance of these two approaches:

* Manual Clone (using the `new` keyword)
* Prototype Extend (using `Object.setPrototypeOf()`)

**Pros and Cons:**

1. **Manual Clone:**
	* Pros:
		+ Easy to understand and implement.
		+ Works well for simple objects with few properties.
	* Cons:
		+ Creates a new object with its own copy of the prototype chain, which can lead to performance issues if the object has many properties or if the prototype chain is deep.
2. **Prototype Extend:**
	* Pros:
		+ More efficient than manual cloning for objects with few properties or shallow prototype chains.
	* Cons:
		+ Can be less intuitive and harder to understand, especially for complex objects.
		+ May lead to performance issues if the object has many properties or a deep prototype chain.

**Library and Purpose:**

The `MergeState` class is used as a test subject for this benchmark. It has two methods:

* `derive1()`: Creates a new instance of `MergeState` using the `new` keyword.
* `derive2()`: Returns an object that shares its prototype with the current instance.

The `base` variable is an instance of `MergeState`.

**Special JS Feature or Syntax:**

This benchmark does not use any special JavaScript features or syntax, such as async/await, generators, or arrow functions.

**Other Alternatives:**

If you're interested in exploring alternative approaches to cloning objects, consider the following:

* Using a library like Lodash's `cloneDeep()` function, which can create a deep copy of an object.
* Using a library like Immutable.js, which provides immutable data structures and operations.
* Implementing your own custom cloning mechanism using JavaScript's built-in methods, such as `JSON.parse(JSON.stringify(obj))` or `Array.prototype.slice.call(obj)`.

Related benchmarks:

Manual clone versus prototype extend (version: 0)

Comparing performance of: Manual clone vs Prototype

Created: 8 years ago by: Registered User

Jump to the latest result

Manual clone

Prototype

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):