Benchmark: Object.assign vs spread operator new object (fixed)

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:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser/OS: Chrome 83 on Windows

View result in a separate tab

Test name	Executions per second
Object.assign	2995577.8 Ops/sec
spread operator	10320246.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and considered.

**Benchmark Overview**

The benchmark compares two approaches for creating a new object: `Object.assign` and the spread operator (`{ ...params }`). The test is designed to measure the performance difference between these two methods on a fixed input dataset.

**Approaches Compared**

There are two approaches being compared:

1. **`Object.assign`**: This method takes multiple arguments and merges them into a new object. In this benchmark, `Object.assign` is used to merge an existing object (`{ a: 2 }`) with a new set of properties (`params`).
2. **Spread Operator (`{ ...params }`)**: This syntax creates a new object by copying the properties from `params` and merging them into the existing object (`{ a: 2 }`).

**Pros and Cons**

**`Object.assign`**:

Pros:

* Widely supported across browsers
* Can be used with older versions of JavaScript that don't support the spread operator

Cons:

* Can be slower than the spread operator due to the overhead of function calls
* May require more code to create a new object, depending on the number of properties being merged

**Spread Operator (`{ ...params }`)**:

Pros:

* Faster and more concise than `Object.assign`
* Is a modern JavaScript feature that's widely supported across browsers (including Chrome 83)

Cons:

* Not supported in older versions of JavaScript
* Requires a specific syntax, which may be unfamiliar to some developers

**Library Usage**

In this benchmark, no libraries are used. The test only involves native JavaScript features.

**Special JS Features/Syntax**

The spread operator (`{ ...params }`) is a modern JavaScript feature that's introduced in ECMAScript 2018 (ES8). It allows for concise object creation by copying properties from an existing object or array.

**Other Considerations**

When choosing between `Object.assign` and the spread operator, consider the following:

* Performance: If speed is critical, the spread operator may be a better choice due to its conciseness and reduced overhead.
* Code readability: If code readability is more important than performance, `Object.assign` may be preferred due to its explicit nature.

**Alternative Approaches**

Other approaches for creating a new object could include:

* Using a library like Lodash or underscore.js
* Using the `Object.create()` method
* Using a template literal (e.g., `const obj = { ... }`)

Related benchmarks:

Object.assign vs spread operator new object (fixed) (version: 0)

Comparing performance of: Object.assign vs spread operator

Created: 4 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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