Benchmark: Object.assign vs spread operator : owntest

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

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The benchmark measures the performance difference between two approaches: `Object.assign` and the spread operator (`...`).

In the test cases, we have an object `params` with properties `b`, `c`, and `d`. The test creates a new object `other` using either `Object.assign` or the spread operator to merge `params` into it.

**Options being compared:**

* `Object.assign`: A method that takes multiple source objects as arguments and merges them into a single object.
* Spread operator (`...`): A syntax feature introduced in ECMAScript 2015, which allows spreading an object's properties onto a new object.

**Pros and Cons of each approach:**

* **`Object.assign()`**:
	+ Pros:
		- Well-established and widely supported method.
		- Can be used to merge objects from multiple sources.
	+ Cons:
		- May not be the most efficient option, especially when dealing with large objects or complex merging scenarios.
		- In some cases, it can create new objects unnecessarily, leading to increased memory allocation.
* **Spread operator (`...`)**:
	+ Pros:
		- More concise and expressive syntax compared to `Object.assign()`.
		- Can be more efficient in terms of object creation, as it only creates a shallow copy of the original object's properties.
	+ Cons:
		- Less well-established and may not work consistently across older browsers or Node.js versions.

**Library usage:**

None of the test cases use any external libraries.

**Special JavaScript features/syntax:**

The benchmark uses the spread operator (`...`), which is a relatively new feature introduced in ECMAScript 2015. This syntax allows spreading an object's properties onto a new object, creating a shallow copy.

**Other considerations:**

* Performance differences between `Object.assign()` and the spread operator can be significant, especially for large objects or complex merging scenarios.
* The benchmark results show that the spread operator is generally faster than `Object.assign()`, but this may vary depending on the specific use case and browser/Node.js version.

**Alternatives:**

* Other methods to merge objects include:
	+ Using a loop to iterate over properties and assign values manually (`for (const key in obj) { other[key] = obj[key]; }`).
	+ Utilizing libraries like Lodash or Underscore.js, which provide optimized merging functions.
	+ Implementing custom merging logic using techniques like Object.create() and prototype chaining.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0

Browser/OS: Firefox 62 on Linux

View result in a separate tab

Test name	Executions per second
Object.assign	2698913.5 Ops/sec
spread operator	2300821.0 Ops/sec

Related benchmarks:

Object.assign vs spread operator : owntest (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>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):