Benchmark: Spread vs Assign bensilverm

Script Preparation code:

function Person(name) {
	this.name = name;
}

Tests:

Spread
const person = new Person("name"); const alsoPerson = {...person}
Object.assign
const person = new Person("name") const alsoPerson = Object.assign(Object.create(Object.getPrototypeOf(person)), person)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided JSON benchmark.

**Benchmark Definition**

The benchmark is comparing two approaches for creating a new object by copying an existing object: using the spread operator (`...`) and using `Object.assign()`.

**Options Compared**

There are two options being compared:

1. **Spread Operator (`...`)**: This syntax creates a new object by taking all the key-value pairs of an existing object and adding them to a new object. For example, given an object `{a: 1, b: 2}`, `{...{a: 1, b: 2}}` would create a new object `{a: 1, b: 2}`.
2. **Object.assign()**: This method copies the properties of one or more source objects to a target object. For example, given an object `person = {name: 'John'}`, `Object.assign({}, person)` would create a new object `{name: 'John'}`.

**Pros and Cons**

Here are some pros and cons of each approach:

**Spread Operator (`...`)**

Pros:

* More concise and readable
* Creates a shallow copy of the original object, which can be faster for simple objects

Cons:

* Can create a deep copy of complex objects if not used carefully (e.g., `{...{a: 1, b: {c: 2}}}` would create a new object with nested properties)
* Not supported in older browsers or Node.js versions

**Object.assign()**

Pros:

* More flexible and powerful for creating complex copies
* Supported in all modern browsers and Node.js versions

Cons:

* Less concise and less readable than the spread operator
* Creates a shallow copy of the original object, which can be slower for simple objects

**Library Used**

In this benchmark, neither of the options relies on any specific library. However, `Object.create()` is used in one of the test cases to create an empty object for `Object.assign()`. `Object.getPrototypeOf()` is also used to get the prototype of the original object.

**Special JS Feature/ Syntax**

None of these options rely on a special JavaScript feature or syntax beyond what's described above. However, it's worth noting that modern browsers and Node.js versions support many other features and syntaxes, such as arrow functions, classes, and async/await.

**Other Alternatives**

Other alternatives for creating new objects by copying existing ones include:

* Using the `JSON.parse()` method to create a shallow copy of an object
* Using the `Array.prototype.slice()` method to create a shallow copy of an array
* Using a library like Lodash or Ramda, which provide more advanced functionality for working with objects and arrays.

It's worth noting that in modern JavaScript, using the spread operator is generally considered the most concise and readable way to create new objects.

Related benchmarks:

Spread vs Assign bensilverm (version: 0)

Comparing performance of: Spread vs Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

Spread

Object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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