Benchmark: JavaScript spread operator vs Object.assign performance fixed 222

Script Preparation code:

var firstObject = {
    "id": "2d10ffad-678b-4f9b-9d7e-1fd57879928d",
    "name": "Gon Freecss",
    "age": 100,
    "wallet": {
      "CNY": {
        "balance": 94306.78,
        "exchangeRate": 4.45
      },
      "USD": {
        "balance": 106.84,
        "exchangeRate": 29.96
      },
      "NTD": {
        "balance": 89171098.51,
        "exchangeRate": 1
      }
    }
  }
var secondObject = {
    "id2": "b8eb86c2-1386-4b91-a87f-a3b16f6ebca5",
    "name2": "Killua Zoldyck",
    "age2": 96,
    "wallet2": {
      "CNY2": {
        "balance2": 59390.08,
        "exchangeRate2": 4.45
      },
      "USD2": {
        "balance2": 446.76,
        "exchangeRate2": 29.96
      },
      "NTD2": {
        "balance2": 49592399.77,
        "exchangeRate2": 1
      }
    }
  }

Tests:

Using the spread operator
const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const finalObject = Object.assign({}, firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using 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):

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Let's dive into the world of JavaScript benchmarks!

**Benchmark Overview**

The provided JSON represents a benchmark test case that compares the performance of two approaches to merge two objects: the spread operator (`...`) and `Object.assign()`. The test case is designed to measure which approach is faster for creating a new object by merging two existing objects.

**Options Compared**

Two options are compared:

1. **Spread Operator (`...`)**: This method uses the rest parameter syntax (`...object`) to merge the properties of two objects into a new object.
2. **Object.assign()**: This method takes multiple source objects and merges their enumerable property values into a single destination object.

**Pros and Cons**

Here's a brief summary of each approach:

* **Spread Operator (`...`)**:
	+ Pros: concise syntax, easy to read and write, can be used with rest parameters.
	+ Cons: might not work as expected in older browsers or environments without modern JavaScript features. Can also lead to unnecessary object creation if not handled carefully.
* **Object.assign()**:
	+ Pros: widely supported across browsers and environments, provides more control over the merging process through its optional arguments (e.g., `Object.assign(dest, ...sources)`).
	+ Cons: can be less concise than the spread operator, may require more effort to set up correctly.

**Library or Special JS Feature**

None of these approaches rely on a specific library. However, both methods utilize modern JavaScript features.

**Test Case Explanation**

The test case creates two objects, `firstObject` and `secondObject`, with similar properties but different values. The benchmark then merges these two objects using each approach and measures the execution time for each method.

* **Using the spread operator**: The code uses the spread operator to merge the properties of `firstObject` and `secondObject` into a new object, `finalObject`.
* **Using Object.assign()**: The code uses `Object.assign()` to merge the properties of `firstObject` and `secondObject` into a new object, `finalObject`.

**Other Alternatives**

If you want to explore other options for merging objects, consider:

1. **Rest parameter syntax (rest parameter spread)**: This method can be used with modern browsers and environments that support rest parameters.
2. **JSON merge libraries**: There are several libraries available that provide a more robust way to merge objects, such as JSON Merge or Lodash.merge.

In conclusion, the benchmark provides an opportunity to compare the performance of two approaches for merging objects in JavaScript: the spread operator (`...`) and `Object.assign()`. By understanding the pros and cons of each approach, you can choose the most suitable method for your specific use case.

Related benchmarks:

JavaScript spread operator vs Object.assign performance fixed 222 (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

Using the spread operator

Using 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):