Benchmark: Object.assign vs spread operator (2)

Tests:

Object.assign
var params = { b:"hello", c: true, d:7 }; var other = Object.assign({ a: 2 }, params);
spread operator
var params = { b:"hello", c: true, d:7 }; var other = { a: 2, ...params };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator

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 break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two approaches for merging objects in JavaScript: `Object.assign` and the spread operator (`...`). The test cases involve creating an object with some properties (`a`, `b`, `c`, `d`) and then using either method to merge it with another object.

**Script Preparation Code**

Since there is no script preparation code provided, we can assume that this benchmark is focused on comparing the performance of these two methods without any additional context or setup.

**Individual Test Cases**

There are two test cases:

1. **Object.assign**: This method takes multiple source objects as arguments and returns a new object with properties from all sources.
```javascript
var params = { b: "hello", c: true, d: 7 };
var other = Object.assign({ a: 2 }, params);
```
This code creates an initial object `{ a: 2 }` and then merges the `params` object into it using `Object.assign`.

Pros:

* Widely supported and well-documented
* Can handle nested objects

Cons:

* May have performance issues if dealing with very large objects or many sources
* Can be brittle if source objects are modified unexpectedly

2. **Spread Operator (`...`)**: This method takes an object as an argument and returns a new object with the same properties, but potentially expanded.
```javascript
var params = { b: "hello", c: true, d: 7 };
var other = { a: 2, ...params };
```
This code creates an initial object `{ a: 2 }` and then merges the `params` object into it using the spread operator.

Pros:

* More concise and expressive than `Object.assign`
* Can be more efficient for small to medium-sized objects
* Less prone to issues with source object modifications

Cons:

* May have performance issues if dealing with very large objects or many sources
* Not supported in older browsers (IE <= 11)

**Library/Features Used**

There is no explicit mention of any libraries or features being used beyond the standard JavaScript `Object.assign` and spread operator. However, it's worth noting that some modern browsers may have additional features or optimizations that could affect performance.

**Special JS Features/Syntax**

None are mentioned explicitly in this benchmark.

**Alternatives**

If you're looking for alternative approaches to merging objects, you might consider:

* Using a library like Lodash, which provides `merge` and other utility functions.
* Implementing your own custom merge function using recursion or iteration.
* Using the `Object.assign()` method with an array of source objects (e.g., `Object.assign({}, ...[object1, object2])`).
* Utilizing modern JavaScript features like `Object.fromEntries()` or `reduce()` for more complex merges.

Keep in mind that these alternatives may have different trade-offs and performance characteristics compared to the spread operator and `Object.assign()`.

Related benchmarks:

Object.assign vs spread operator (2) (version: 0)

Comparing performance of: Object.assign vs spread operator

Created: 6 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

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):