Benchmark: Object.keys vs for ... in

Script Preparation code:

window.objectKeys = (value) => {
    return Object.keys(value).length > 0
}

window.isEmpty = (value) => {
    if (!value) {
        return true;
    }

    for (const key in value) {
        if (Object.hasOwn(value, key)) {
            return false;
        }
    }

    return true;
}

Tests:

window.objectKeys
const obj = { mr: 1, ml: 1, p: 1 } window.objectKeys(obj)
window.isEmpty
const obj = { mr: 1, ml: 1, p: 1 } window.isEmpty(obj)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
window.objectKeys
window.isEmpty

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:144.0) Gecko/20100101 Firefox/144.0

Browser/OS: Firefox 144 on Linux

View result in a separate tab

Test name	Executions per second
window.objectKeys	3552904.0 Ops/sec
window.isEmpty	3271011.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 months ago):

LLMs can make mistakes. Check important info.

In this benchmark, we are testing the performance of two different approaches to checking if an object is empty in JavaScript: using `Object.keys()` and a `for...in` loop.

### Options Compared:

1. **Using `Object.keys()`**:
   - The method `window.objectKeys` checks if an object has keys by utilizing `Object.keys(value)`, which returns an array of an object's own enumerable property names. The benchmark then determines if the length of this array is greater than zero to establish whether the object is empty.
   
2. **Using `for...in` Loop**:
   - The method `window.isEmpty` uses the `for...in` loop to iterate over the keys of an object. It leverages `Object.hasOwn()` to check if the object has its own properties. The function returns false if it finds any own properties, indicating that the object is non-empty.

### Pros and Cons:

#### 1. Using `Object.keys()`:
   - **Pros**:
     - It is more straightforward and easier to read and understand.
     - Since it directly creates an array of keys, it can be more performant for objects with many properties, as it avoids needing to check each property individually during an iteration.
   
   - **Cons**:
     - It creates an additional array in memory, which may add overhead, particularly if used frequently on large objects.

#### 2. Using `for...in` Loop:
   - **Pros**:
     - This method does not create another array, making it potentially more memory efficient for larger objects if they contain a large number of properties.
     - In scenarios where performance on large datasets is critical and objects typically have many properties, this approach may be faster.
   
   - **Cons**:
     - The syntax can be more complex and less readable, especially for developers who may not be as familiar with JavaScript idioms.
     - There’s also a risk of iterating over inherited properties unless proper checks (like `Object.hasOwn()`) are implemented.

### Other Considerations:
- Performance can vary based on the JavaScript engine and the context in which these functions are called (e.g., in a browser versus a server environment).
- Using libraries or tools designed for performance benchmarks or optimizations (like Lodash or Underscore.js) might provide more utility functions to check object properties but may add overhead based on the library's size.
- Other alternatives to checking if an object is empty could be leveraging methods like `Object.entries()` or `Object.values()`, which also return arrays, combined with length checks. However, they also create arrays and hold similar pros and cons as `Object.keys()`.

### Results Analysis:
From the latest benchmark results, we can observe the following:
- `window.objectKeys` was able to execute approximately 46.4 million times per second.
- In contrast, `window.isEmpty` executed around 35.8 million times per second.

This indicates that while both methods are relatively efficient, using `Object.keys()` potentially offered better performance in this particular benchmark scenario on a mobile Chrome browser environment. However, the actual performance may differ based on the size and structure of objects being evaluated in practical applications.

Related benchmarks:

Object.keys vs for ... in (version: 1)

Comparing performance of: window.objectKeys vs window.isEmpty

Created: 6 months ago by: Guest

Jump to the latest result

window.objectKeys

window.isEmpty

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 months ago):