Benchmark: object-spread vs object-assign

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } 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:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36

Browser/OS: Chrome 91 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using the spread operator	5125532.0 Ops/sec
Using Object.assign	9235240.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is comparing two ways to merge two objects: using the spread operator (`...`) and using `Object.assign()`.

**Options Compared**

1. **Spread Operator**: The spread operator is a new syntax introduced in ECMAScript 2018 (ES8) that allows you to expand an object's properties into another object.
2. **Object.assign()**: This is a built-in JavaScript method that merges two or more objects into one.

**Pros and Cons**

1. **Spread Operator**:
	* Pros: More concise, readable, and expressive than `Object.assign()`. It also provides a way to create new objects with a subset of properties.
	* Cons: May be slower due to the overhead of creating a new array with the object's properties.
2. **Object.assign()**:
	* Pros: Widely supported, easy to use, and efficient for large datasets.
	* Cons: Less concise than the spread operator and can be harder to read.

**Library**

None are mentioned in the benchmark definition. However, it's worth noting that `Object.assign()` is a built-in JavaScript method, so no library is required.

**Special JS Feature or Syntax**

The spread operator (`...`) is a new syntax introduced in ECMAScript 2018 (ES8). It allows you to expand an object's properties into another object. This feature is not available in older versions of JavaScript.

**Other Alternatives**

If you don't want to use the spread operator, you can also use other methods to merge objects, such as:

1. **Using `for...in` loop**: You can iterate over the properties of one object and add them to another object using a `for...in` loop.
2. **Using `Object.keys()` and `reduce()`**: You can get the keys of both objects and use `Object.keys()` and `reduce()` to merge them into a new object.

Here's an example of how you could implement these alternatives:
```javascript
// Using for...in loop
const finalObject = {};
for (let key in firstObject) {
  finalObject[key] = firstObject[key];
}
finalObject[...]secondObject;

// Using Object.keys() and reduce()
const keys = Object.keys(firstObject).concat(Object.keys(secondObject));
const mergedObject = keys.reduce((acc, key) => {
  acc[key] = firstObject[key] || secondObject[key];
  return acc;
}, {});
```
Keep in mind that these alternatives may not be as concise or readable as using the spread operator.

Related benchmarks:

object-spread vs object-assign (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>

Experimental features:

Fastest: N/A

Slowest: N/A

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