Benchmark: function+for-in vs Object.keys

Script Preparation code:

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

Tests:

for-in function returning array of keys.
function objectKeys(obj) { let arr = []; for (var key in obj) arr.push(key); return (arr); } for (var i=1000; i > 0; i--) { objectKeys(obj); }
Object.keys()
for (var i=1000; i > 0; i--) { Object.keys(obj); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for-in function returning array of keys.
Object.keys()

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what is being tested, the different approaches compared, and their pros and cons.

**Benchmark Definition:**
The benchmark measures the performance difference between two approaches:

1. **Using a `for-in` loop with a function**: This approach iterates over an object using a `for-in` loop and pushes each key into an array.
2. **Using `Object.keys()`**: This approach uses the built-in `Object.keys()` method to get an array of keys from an object.

**Script Preparation Code:**
The script preparation code defines an object `obj` with 7 properties, all set to 1.

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

**Html Preparation Code:**
There is no HTML preparation code provided.

**Individual Test Cases:**

### Case 1: `for-in function returning array of keys.`
```javascript
function objectKeys(obj) {
    let arr = [];
    for (var key in obj)
        arr.push(key);
    return arr;
}

for (var i = 1000; i > 0; i--) {
    objectKeys(obj);
}
```

This test case measures the performance of a custom `objectKeys()` function that iterates over an object using a `for-in` loop and pushes each key into an array.

### Case 2: `Object.keys()`
```javascript
for (var i = 1000; i > 0; i--) {
    Object.keys(obj);
}
```

This test case measures the performance of the built-in `Object.keys()` method to get an array of keys from an object.

**Pros and Cons:**

* **Using a `for-in` loop with a function**:
	+ Pros: Customizable, allows for more control over the iteration process.
	+ Cons: May be slower due to the overhead of creating and pushing elements into an array.
* **Using `Object.keys()`**:
	+ Pros: Built-in method, optimized for performance, easy to use.
	+ Cons: Limited control over the iteration process.

**Library:**
There is no external library being used in these test cases. The `Object.keys()` method is a built-in JavaScript method.

**Special JS Feature/Syntax:**
None of the provided code uses any special JavaScript features or syntax, such as async/await, let, const, etc.

**Alternatives:**
Other alternatives to measure the performance difference between these two approaches could include:

* Using other iteration methods, such as `forEach()` or a custom iterator.
* Adding additional processing steps after iterating over the object's keys.
* Using different data structures, such as an array of objects instead of a single object.

Note that the specific alternative test cases would depend on the goals and requirements of the benchmark.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Browser/OS: Chrome 67 on Windows

View result in a separate tab

Test name	Executions per second
for-in function returning array of keys.	9815.6 Ops/sec
Object.keys()	4061.9 Ops/sec

Related benchmarks:

function+for-in vs Object.keys (version: 0)

Performance Benchmark of a Function with a for-in loop vs Object.keys

Comparing performance of: for-in function returning array of keys. vs Object.keys()

Created: 6 years ago by: Guest

Jump to the latest result

for-in function returning array of keys.

Object.keys()

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):