Benchmark: for-in vs object.keysdvsdv

Script Preparation code:

var obj = {
  'a': 1,
  'b': 1,
  'c': 1,
  'd': 1,
  'e': 1,
  'f': 1,
  'g': 1
};

var b = {}

Tests:

for-in
for (var i=10000; i > 0; i--) { for (var key in obj) { b[key] = obj[key] } }
Object.keys
for (var i=10000; i > 0; i--) { for (let key of Object.keys(obj)) { b[key] = obj[key] } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for-in
Object.keys

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that compares the performance of two approaches: `for-in` loop and `Object.keys()` method for iterating over an object's properties.

**Options compared:**

1. **For-in loop**: This approach uses the `in` operator to iterate over an object's own enumerable properties (i.e., its keys).
2. **Object.keys() method**: This approach uses a built-in JavaScript function, `Object.keys()`, to get an array of an object's own enumerable property names.

**Pros and Cons:**

* **For-in loop**:
	+ Pros: Can be used with any type of object, including non-iterable objects like arrays or functions.
	+ Cons: May not work as expected in certain edge cases (e.g., when the object has a `length` property), can lead to unexpected behavior if not used carefully.
* **Object.keys() method**:
	+ Pros: Explicitly iterates over properties, which can improve performance and readability. Works with most types of objects.
	+ Cons: May have a slight performance overhead due to its function call.

**Library and syntax:**

There is no explicit library mentioned in the provided code snippets. However, it's worth noting that `Object.keys()` is a built-in JavaScript function.

**Special JS feature or syntax:**

There are no special features or syntaxes used in this benchmark.

**Considerations:**

When choosing between these two approaches, consider the following:

* If you need to iterate over an object's properties and want a more explicit control, use `Object.keys()`.
* If you're working with a legacy codebase or need to support older browsers, the `for-in` loop might be a better choice.

**Other alternatives:**

If you want to explore other options, consider:

1. **Using `forEach()` method**: This approach can provide an alternative way to iterate over an object's properties using an iterator.
2. **Using `for...of` loop**: This is another iterative syntax that provides a concise and expressive way to iterate over arrays or objects.

Here's some sample code for each of these alternatives:
```javascript
// Using forEach()
const obj = {a: 1, b: 2, c: 3};
obj.forEach((value) => console.log(value));

// Using for...of loop (with Object.entries())
const objEntries = Object.entries(obj);
for (const [key, value] of objEntries) {
    console.log(key, value);
}
```

Related benchmarks:

for-in vs object.keysdvsdv (version: 0)

Comparing performance of: for-in vs Object.keys

Created: 4 years ago by: Guest

Jump to the latest result

for-in

Object.keys

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):