Benchmark: Spread vs Assign benchmark

Tests:

Basic object spread
const obj = { foo: 1, bar: 2 }; const finalObject = ({ baz: 3, ...obj })
Basic assign operator
const obj = { foo: 1, bar: 2 }; const finalObject = Object.assign({baz: 3}, obj);
Assign with empty object
const obj = { foo: 1, bar: 2 }; Object.assign({}, obj, { baz: 3 });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Basic object spread
Basic assign operator
Assign with empty object

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/94.0.4606.61 Safari/537.36

Browser/OS: Chrome 94 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Basic object spread	7249307.5 Ops/sec
Basic assign operator	2133161.5 Ops/sec
Assign with empty object	1288553.6 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a JavaScript benchmark test case on MeasureThat.net, titled "Spread vs Assign benchmark". The test compares three different approaches to merge two objects in JavaScript: using the spread operator (`...`), the assignment operator (`=`), and a combination of assigning to an empty object.

**Approaches Compared**

1. **Basic Object Spread**: This approach uses the spread operator (`{ ... }`) to create a new object that includes all properties from `obj`, with additional properties added from the `{ baz: 3, ...obj }` expression.
2. **Basic Assign Operator**: This approach uses the assignment operator (`=`) to merge two objects. The syntax is similar to the previous one, but instead of using the spread operator, it assigns `obj` directly to a new object created with `Object.assign()`.
3. **Assign with Empty Object**: This approach creates an empty object `{}` and then uses the assignment operator to merge it with another object.

**Pros and Cons**

* **Basic Object Spread**:
	+ Pros: Easy to read, concise syntax.
	+ Cons: May be slower than other approaches due to the overhead of creating a new object.
* **Basic Assign Operator**:
	+ Pros: Can be faster than spread operator due to less overhead, but may require more memory allocation.
	+ Cons: Less readable and verbose compared to spread operator.
* **Assign with Empty Object**:
	+ Pros: Similar performance to Basic Assign Operator, but can be slightly slower due to the additional object creation.
	+ Cons: Requires creating an empty object, which can lead to extra memory allocations.

**Other Considerations**

When choosing between these approaches, consider factors like readability, performance, and maintainability. For most use cases, the spread operator is a clear winner in terms of simplicity and conciseness. However, in specific situations where memory efficiency or fast execution are crucial, the assignment operator or Assign with Empty Object might be more suitable.

**Libraries Used**

None of these test cases explicitly uses any third-party libraries. The JavaScript engine's built-in objects and operators (`Object.assign()`, spread operator) are used throughout the benchmark.

**Special JS Features/Syntax**

The benchmark does not use any special JavaScript features or syntax beyond what is standard in modern JavaScript. It only relies on basic language constructs, making it accessible to a wide range of developers without deep knowledge of JavaScript.

Related benchmarks:

Spread vs Assign benchmark (version: 0)

Comparing performance of: Basic object spread vs Basic assign operator vs Assign with empty object

Created: 3 years ago by: Guest

Jump to the latest result

Basic object spread

Basic assign operator

Assign with empty object

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):