Benchmark: json stringify parse vs spread

Script Preparation code:

function makeTestData() { return { name: "Matheus de Sousa Martins", age: 30, phone: "999999999999" }; }

Tests:

toString
let a = {...makeTestData()}
JSON.stringify
JSON.parse(JSON.stringify(makeTestData()));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
toString
JSON.stringify

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser/OS: Chrome 138 on Windows

View result in a separate tab

Test name	Executions per second
toString	48496012.0 Ops/sec
JSON.stringify	2694800.2 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark you're looking at compares two different methods of creating a clone of an object in JavaScript: using the spread operator and using JSON serialization (stringify and parse).

### Test Cases Overview

1. **Spread Operator**: 
   - **Test Case**: `let a = {...makeTestData()}`
   - **Test Name**: `toString`
   - **Description**: This method uses the spread operator (`...`) to create a shallow copy of the object generated by the `makeTestData()` function. The spread operator takes all the properties of the object returned by the function and puts them into a new object.
   - **Pros**: 
     - Very concise and readable syntax.
     - Allows for copying only the properties of the object, and thus maintains the original object for further use.
     - Handles arrays and nested objects, but only shallowly.
   - **Cons**: 
     - If the original object contains nested objects, the nested objects will still be references in the new object. Thus, modifications to nested objects will affect both the original and the copied object.

2. **JSON Serialization**:
   - **Test Case**: `JSON.parse(JSON.stringify(makeTestData()));`
   - **Test Name**: `JSON.stringify`
   - **Description**: This method converts the object to a JSON string and then parses that string back into a new object. This results in a deep copy of the original object, because the entire object structure is converted to a string and then reconstructed.
   - **Pros**: 
     - Creates a deep copy of the object, meaning nested objects are also copied, and modifications to the new object will not affect the original.
     - Good for simple data structures that are JSON-serializable.
   - **Cons**: 
     - Can be less efficient than the spread operator, especially with large objects or a high frequency of operations, due to the overhead of string conversion.
     - Not all objects can be serialized to JSON (e.g., functions, `undefined`, special objects such as `Date` and `RegExp`).
     - Can lose information for certain JavaScript types (like `Date`, `undefined`, or geometry info).

### Benchmark Results
The benchmark results show the execution speed of both approaches measured in executions per second:

- **Spread Operator** (`toString`):
  - **Executions Per Second**: Approximately 74 million
- **JSON Serialization** (`JSON.stringify`):
  - **Executions Per Second**: Approximately 2.8 million

This significant difference in execution speed indicates that using the spread operator is much faster for this specific operation.

### Other Considerations
- The choice between these two methods should be guided by the specific use case:
  - If you need a shallow copy and performance is critical, the spread operator is preferred.
  - If you require a deep copy and are not too concerned about performance, JSON serialization is the way to go.
- Alternative methods for deep cloning include using utility libraries like Lodash (`_.cloneDeep()`), or creating custom deep cloning functions that handle specific object types manually.

### Conclusion
In summary, this benchmark provides valuable insight into the performance characteristics of two commonly used object copying methods in JavaScript. Understanding the pros and cons of these approaches equips software engineers with the knowledge needed to make informed decisions depending on their application's requirements for speed and data integrity.

Related benchmarks:

json stringify parse vs spread (version: 1)

Comparing performance of: toString vs JSON.stringify

Created: one year ago by: Guest

Jump to the latest result

toString

JSON.stringify

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):