Benchmark: destructuring vs for-in

Script Preparation code:

var props = {key: 1, ref: () => {}, a: 1, b: "b", children: ["hello world"]};

Tests:

destructuring
const {key, ref, ...props1} = props;
for...in
let key; let ref; const props1 = {}; for (const name in props) { if (name === "key") { key = props[name]; } else if (name === "ref") { ref = props[name]; } else { props1[name] = props[name]; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
destructuring
for...in

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.1 Safari/605.1.15

Browser/OS: Safari 13 on Mac OS X 10.14.6

View result in a separate tab

Test name	Executions per second
destructuring	1010653.6 Ops/sec
for...in	1027768.1 Ops/sec

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

LLMs can make mistakes. Check important info.

**What is being tested?**

On the provided JSON, two test cases are defined to compare the performance of JavaScript destructuring vs traditional for-in loop.

**Options compared:**

1. **Destructuring**: A syntax sugar in JavaScript that allows you to extract multiple values from an object in a concise and readable way.
2. **For-in loop**: A traditional method used to iterate over the properties of an object, where each iteration is done on a specific property at a time.

**Pros and Cons:**

* **Destructuring**:
	+ Pros:
		- More concise and readable code
		- Often faster than for-in loops due to fewer function calls
		- Reduces clutter with explicit variable declarations
	+ Cons:
		- May require modern JavaScript engines (ES6+) that support this syntax
		- Can be more complex to understand, especially for beginners or those not familiar with the syntax
* **For-in loop**:
	+ Pros:
		- More widely supported across different JavaScript engines and versions
		- Tightly coupled with the object being iterated over (i.e., no need to declare separate variables)
	+ Cons:
		- Often more verbose than destructuring
		- Requires explicit variable declarations, which can be cluttered

**Library and purpose:**

None mentioned in this benchmark.

**Special JS feature or syntax:**

* **Destructuring**: JavaScript's ES6+ introduction (added with the "destructuring assignment" feature). This allows you to assign values from an object into multiple variables in a single line of code. The syntax for destructuring is `const { variableName, anotherVariableName } = object;` or `let { variableName, anotherVariableName } = object;`.

**Other alternatives:**

For iterating over objects' properties, other alternatives to the for-in loop include:

* **Array.prototype.forEach()**: A more modern and concise method that's often used with arrays.
* **Object.keys()**, **Object.values()**, or **Object.entries()**: These methods return an array of keys/values/entries in the object, allowing you to iterate over them in a more readable way.

Keep in mind that these alternatives might have slightly different performance characteristics compared to the for-in loop.

Related benchmarks:

destructuring vs for-in (version: 0)

Comparing performance of: destructuring vs for...in

Created: 4 years ago by: Guest

Jump to the latest result

destructuring

for...in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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