Benchmark: desctruct vs property assign

Script Preparation code:

var obj = {};
var count = 100000;
for(var i = 0; i < count; i++)
{
  obj[i] = {};
}

Tests:

destruct
Object.entries(obj).reduce((acc, [key, value]) => ({ ...acc, [key]: value }), {})
property assign
Object.entries(obj).reduce((acc, [key, value]) => { acc[key] = value; return acc; }, {})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
destruct
property 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):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

The benchmark is comparing two approaches to assign values to an object in JavaScript:

1. **Destructuring assignment**: The first approach uses destructuring syntax to assign values to an object. Specifically, the line `({ ...acc, [key]: value })` creates a new object with the existing properties of `acc` and adds the new property `[key] = value;`. This is equivalent to doing `{ acc[key] = value; return acc }`, but it's often considered more readable.
2. **Property assignment**: The second approach uses traditional property assignment syntax, where `acc[key] = value;` directly assigns a value to an existing property of the object.

Now, let's discuss the pros and cons of each approach:

**Destructuring assignment**

Pros:

* More concise and readable code
* Can be more efficient since it avoids the need for explicit property name resolution

Cons:

* May not work as expected if the object doesn't have a property with that name
* Can lead to unexpected behavior if the destructured object is mutated in unintended ways

**Property assignment**

Pros:

* More predictable and controlled behavior, especially when working with existing objects
* Allows for more explicit control over property names and values

Cons:

* Can be less concise and less readable than destructuring assignment
* May require more boilerplate code to achieve the same result as destructuring assignment

Other considerations:

* Both approaches have the same time complexity, O(n), where n is the number of properties being assigned.
* However, the destructuring approach may perform slightly better in practice due to its concise syntax and potential for faster property name resolution.

In the provided benchmark results, Chrome 107 performs significantly better (44.81 executions per second) on the `property assign` approach compared to the `destruct` approach (0.02711 executions per second). This suggests that destructuring assignment may be slower in practice due to its concise syntax and potential for more complex property name resolution.

The benchmark doesn't use any external libraries, so there's no library-related considerations to discuss. However, if you were to add a library or framework-specific feature, it would depend on the specific library and how it interacts with JavaScript.

As for special JS features or syntax, this benchmark only uses standard JavaScript features without any notable exceptions.

Related benchmarks:

desctruct vs property assign (version: 0)

((acc, key) => ({ ...acc, [key]: value}) vs { acc[key] = value; return acc }

Comparing performance of: destruct vs property assign

Created: 3 years ago by: Guest

Jump to the latest result

destruct

property 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):