Benchmark: JavaScript for vs Object.assign performance

Tests:

Using the for ... in operator
const firstObject = { sampleData: 'Hello world' } const finalObject = {}; for (const key in firstObject) { finalObject[key] = firstObject[key]; }
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const finalObject = Object.assign({}, firstObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the for ... in operator
Using Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and its test cases.

**What is tested?**

The provided JSON represents two JavaScript microbenchmarks that compare the performance of two approaches for iterating over objects: using the `for...in` operator versus using the `Object.assign()` method.

**Options compared**

There are two options being compared:

1. **Using the `for...in` operator**: This approach uses a traditional `for` loop with an `in` clause to iterate over the object's properties and assign them to a new object.
2. **Using `Object.assign()`**: This approach uses the spread operator (`{}`) to create a shallow copy of an object and then iterates over its properties using the spread operator.

**Pros and Cons**

* **Using the `for...in` operator**:
	+ Pros: More intuitive and readable, as it allows developers to explicitly specify the iteration order.
	+ Cons: Can be slower due to the overhead of iterating over the object's properties using `in`.
* **Using `Object.assign()`**:
	+ Pros: Faster, as it uses a built-in method optimized for shallow copying objects.
	+ Cons: Less intuitive and less readable, as the spread operator can be cryptic.

**Library usage**

None of the provided benchmark test cases use any external libraries. The only library used is JavaScript's built-in `Object.assign()` function.

**Special JS feature or syntax**

There are no special JavaScript features or syntax mentioned in the provided test cases. Both approaches use standard JavaScript syntax and methods.

**Other considerations**

When choosing between these two approaches, consider the following:

* Readability: If code readability is more important than performance, using the `for...in` operator might be a better choice.
* Performance: If speed is crucial, using `Object.assign()` could provide a slight advantage due to its optimized implementation.

**Alternatives**

Other alternatives for iterating over objects include:

1. **Using `for...of` loops**: Introduced in ECMAScript 2015 (ES6), these loops allow developers to iterate directly over object properties without the need for `in`.
2. **Using array methods**: For arrays, you can use `forEach()`, `map()`, or `reduce()` instead of a traditional loop.

In conclusion, the choice between using the `for...in` operator and `Object.assign()` ultimately depends on the specific requirements of your project, such as performance, readability, and the nature of your data.

Related benchmarks:

JavaScript for vs Object.assign performance (version: 0)

for ... in vs Object.assign

Comparing performance of: Using the for ... in operator vs Using Object.assign

Created: 5 years ago by: Guest

Jump to the latest result

Using the for ... in operator

Using Object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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