Benchmark: for let vs Object.keys 3

Script Preparation code:

var myObject = {};
var sum = 0;

for (let i = 0; i < 1000; i++)
    myObject["property_" + Math.random()] = Math.random();

var keys = Object.keys(myObject);

Tests:

Object.keys
sum = 0; const newKeys = Object.keys (myObject); for (let i = 0 ; i < newKeys.length ; i++) sum += myObject[newKeys[i]];
Object.keys (cached)
sum = 0; for (let i = 0 ; i < keys.length ; i++) sum += myObject[keys[i]];
for let i in
sum = 0; for (let i in myObject) sum += myObject[i];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.keys
Object.keys (cached)
for let i in

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Whale/3.26.244.21 Safari/537.36

Browser/OS: Chrome 124 on Windows

View result in a separate tab

Test name	Executions per second
Object.keys	3759.9 Ops/sec
Object.keys (cached)	3067.2 Ops/sec
for let i in	3650.7 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The benchmark compares three different approaches to iterate over an object's properties:

1.  **For Loop with Object Keys**: This approach uses the `Object.keys()` method to get an array of the object's property names, and then iterates over this array using a for loop.
2.  **For Loop with Iterating Over Property Names Directly**: This approach iterates directly over the object's properties using a for loop without relying on `Object.keys()`.
3.  **For Loop with Object Keys (Cached)**: This is an optimized version of the first approach, which caches the result of `Object.keys()` to avoid recalculating it every time.

**Approach Comparison**

### For Loop with Object Keys

*   **Pros**: 
    *   Easy to read and maintain
    *   Works well for small to medium-sized objects
*   **Cons**: 
    *   Can be slow for large objects due to the overhead of `Object.keys()` and iterating over an array
    *   May not be suitable for very large or complex objects

### For Loop with Iterating Over Property Names Directly

*   **Pros**:
    *   Faster execution speed compared to using `Object.keys()`
    *   Suitable for large objects, as it avoids the overhead of iterating over an array
*   **Cons**: 
    *   May be harder to read and maintain due to the direct iteration syntax
    *   Error-prone if not handled carefully

### For Loop with Object Keys (Cached)

*   **Pros**:
    *   Optimized for performance by caching the result of `Object.keys()`
    *   Suitable for large or complex objects, as it reduces overhead compared to using `Object.keys()` directly
*   **Cons**: 
    *   May not be suitable for very small objects due to the cache size

**Library Usage**

None of the provided benchmark test cases use any external libraries. However, if you were to extend this benchmark or add new tests, some JavaScript libraries that could be useful include:

*   Lodash: Provides utility functions like `Object.keys()` and other convenience functions.
*   moment.js: For date-related calculations.

**Special JS Features/Syntax**

The provided test cases do not use any special JavaScript features or syntax beyond the standard for loop and object iteration syntax. If you were to add new tests, you might consider using more advanced concepts like:

*   Async/Await: For handling asynchronous code
*   Promises: For handling promises and asynchronous operations

**Alternatives**

If you're looking for alternative benchmarking tools or libraries to compare performance in your JavaScript projects, some popular options include:

*   BenchmarkJS: A cross-browser benchmarking library that provides a simple API for running benchmarks.
*   jsbench: An online JavaScript benchmarking tool with support for asynchronous tests and caching.
*   perf.js: A lightweight benchmarking library that allows you to compare performance of different code snippets.

Note that each of these alternatives has its own strengths, weaknesses, and use cases.

Related benchmarks:

for let vs Object.keys 3 (version: 0)

Comparing performance of: Object.keys vs Object.keys (cached) vs for let i in

Created: one year ago by: Guest

Jump to the latest result

Object.keys

Object.keys (cached)

for let i in

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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