Benchmark: Test: Object.assign vs. JSON String/Parse

Tests:

Spread operator
var n = {foo: 'bar', hello: [{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'}]}; while(n.length < 1000) { n = [...n]; }
JSON Parse
var n = {foo: 'bar', hello: [{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'}]}; n = JSON.stringify(n); var j = JSON.parse(n)
Object.assign
var n = {foo: 'bar', hello: [{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'}]}; while(n.length < 1000) { n = Object.assign({}, n); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread operator
JSON Parse
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:79.0) Gecko/20100101 Firefox/79.0

Browser/OS: Firefox 79 on Windows

View result in a separate tab

Test name	Executions per second
Spread operator	18603810.0 Ops/sec
JSON Parse	342157.7 Ops/sec
Object.assign	23937398.0 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 and explain what is tested, the options compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark tests three different approaches to create a new object reference:

1. **Object.assign**: Uses the `Object.assign` method to create a shallow copy of an object.
2. **Spread Operator (JSON Parse)**: Uses the spread operator (`...`) to create a deep copy of an object by converting it to a JSON string and then parsing it back into an object.
3. **JSON String/Parse**: Directly converts an object to a JSON string using `JSON.stringify` and then parses it back into an object using `JSON.parse`.

**Options Compared**

The three options are compared in terms of their performance (executions per second) on a Windows Desktop with Firefox 79 browser.

**Pros and Cons of Each Approach**

1. **Object.assign**:
	* Pros: Fast and efficient, well-supported by most modern browsers.
	* Cons: Only creates a shallow copy, which may not be suitable for all use cases.
2. **Spread Operator (JSON Parse)**:
	* Pros: Creates a deep copy, which can be useful in certain scenarios. However, the process of converting to JSON and parsing back can introduce overhead.
	* Cons: May not be as efficient as `Object.assign`, especially for large objects. The spread operator is also supported by most modern browsers, but its performance can vary depending on the browser and JavaScript engine.
3. **JSON String/Parse**:
	* Pros: Creates a deep copy, similar to the spread operator approach. However, it bypasses the need for parsing JSON, which can reduce overhead.
	* Cons: May not be as efficient as `Object.assign` or the spread operator, especially for large objects.

**Other Considerations**

* **Memory Usage**: Creating a new object reference using `Object.assign`, the spread operator, or `JSON.Stringify/Parse` will allocate memory on the heap. The amount of memory allocated depends on the size and complexity of the original object.
* **Browser Support**: All three options are supported by most modern browsers, but their performance can vary depending on the browser and JavaScript engine.

**Library Used**

None of the benchmark options use a specific library. However, `JSON.stringify` and `JSON.parse` rely on the JSON specification, which is maintained by the Internet Engineering Task Force (IETF).

**Special JS Feature or Syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 and has since become a widely supported feature across most modern browsers.

**Benchmark Preparation Code and Test Cases**

The benchmark preparation code is empty for all three test cases, indicating that the focus is solely on measuring the performance of each approach. The individual test cases provide different approaches to create a new object reference, with varying degrees of complexity:

1. A simple object with a single property.
2. An object with multiple properties, including arrays and nested objects.

The benchmark results show the executions per second for each browser, providing insight into the relative performance of each approach on this specific use case.

Related benchmarks:

Test: Object.assign vs. JSON String/Parse (version: 1)

Creating a "new" object reference every time

Comparing performance of: Spread operator vs JSON Parse vs Object.assign

Created: 4 years ago by: Registered User

Jump to the latest result

Spread operator

JSON Parse

Object.assign

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):