Benchmark: Shallow Object Merge fixed

Tests:

Spread operator
const obj1 = { foo: 'pikachu' } const obj2 = { bar: 'charizard' } const result = { ...obj1, ...obj2 }
Object.assign with non-predefined target
const obj1 = { foo: 'pikachu' } const obj2 = { bar: 'charizard' } const result = Object.assign({}, obj1, obj2)
Object.assign with predefined target
const obj1 = { foo: 'pikachu' } const obj2 = { bar: 'charizard' } const target = {} const result = Object.assign({}, obj1, obj2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread operator
Object.assign with non-predefined target
Object.assign with predefined target

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/94.0.4606.81 Safari/537.36 Edg/94.0.992.50

Browser/OS: Chrome 94 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Spread operator	2101226.5 Ops/sec
Object.assign with non-predefined target	5000084.0 Ops/sec
Object.assign with predefined target	4866714.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested on the provided JSON.

The benchmark is testing three different ways to merge two objects in JavaScript:

1. **Spread Operator**: The first test case uses the spread operator (`...`) to merge `obj1` and `obj2`. This approach was introduced in ECMAScript 2018 (ES10) as a part of the Object Rest/Spread syntax.

Pros:
* Concise and readable syntax.
* Supports merging multiple objects into one.

Cons:
* Requires modern JavaScript versions (ECMAScript 2018+).
* Can be slower due to the overhead of parsing the spread operator.

2. **Object.assign with non-predefined target**: The second test case uses `Object.assign()` with no target object provided, which means it creates a new empty object (`{}`) and merges `obj1` into it, followed by merging `obj2` into that resulting object.

Pros:
* Widely supported across older JavaScript versions.
* Still relatively fast since the spread operator is only used once.

Cons:
* Requires an extra step to create the target object.
* May be slower than other approaches due to the overhead of creating and merging objects.

3. **Object.assign with predefined target**: The third test case uses `Object.assign()` with a predefined empty target object (`{}`). This approach merges both `obj1` and `obj2` directly into the same target object without any intermediate steps.

Pros:
* Similar performance to non-predefined `Object.assign()` since there's no overhead from creating an extra object.
* Still widely supported across older JavaScript versions.

Cons:
* Requires specifying an empty target object explicitly, which can be a source of errors if not done correctly.

**Other considerations:**

* Memory allocation and garbage collection are also affected by these approaches. For example, the spread operator creates a new object, while `Object.assign()` creates an intermediate copy (if using non-predefined target) or modifies the existing object.
* The benchmark results show that `Object.assign()` with predefined target is the fastest among the three approaches.

**Library and purpose:**

The `Object` constructor and its methods (`assign()`, `Spread`) are built-in JavaScript libraries. They provide basic functionality for working with objects in a predictable way, which makes them essential for any modern web development project.

**Special JS feature or syntax:**

The spread operator (in the first test case) is a new JavaScript feature introduced in ECMAScript 2018 (ES10). It allows for more concise object merging and destructuring.

Related benchmarks:

Shallow Object Merge fixed (version: 0)

Comparing performance of: Spread operator vs Object.assign with non-predefined target vs Object.assign with predefined target

Created: 3 years ago by: Guest

Jump to the latest result

Spread operator

Object.assign with non-predefined target

Object.assign with predefined target

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):