Benchmark: Object.keys + map vs for...in + push

Script Preparation code:

var data = [
  {
    "SDGHDJJ": "FDSFSDF",
    "FDSDS": "GFDGFDG",
    "5SDFFD": "GFDGDFG",
    "353G": "THFGJGFGF",
    "6BDFSD": "GFDDWERT",
    "53523FV": "HGFHGFHFGHF",
    "FSDGSDGS4": "FDSFDTYF",
    "532523GSV": "SADAHHDFG",
    "253GSG": "GFDGDFHDF",
    "ADFGJKU5": "GDFJKTRRW",
    "354GFG": "DSFSDHRRR"
  }
];
var result = [];

Tests:

Object.keys + map
result = Object.keys(data[0]).map(prop => ( { wch: Math.max(prop.toString().length, ...data.map(obj => obj[prop] ? obj[prop].toString().length : 0)) } ));
for...in + push
for (const prop in data[0]) { const maxWidth = Math.max(prop.toString().length, ...data.map(obj => obj[prop] ? obj[prop].toString().length : 0)); result.push({ wch: maxWidth }); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.keys + map
for...in + push

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 JSON and explain what's being tested.

**Benchmark Definition**

The benchmark is comparing two approaches to find the maximum length of a string within an array of objects:

1. **Object.keys + map**: This approach uses `Object.keys()` to get an array of property names from the first object in the `data` array, and then uses `map()` to create a new array with the maximum length of each property name.
2. **for...in + push**: This approach uses a traditional `for...in` loop to iterate over the properties of the first object in the `data` array, and then pushes the maximum length of each property name into an array called `result`.

**Comparison**

The two approaches are being compared to determine which one is faster. The benchmark will run both approaches multiple times and report the average execution time for each.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **Object.keys + map**:
	+ Pros: More concise, readable, and expressive code. Uses modern JavaScript features like `map()`.
	+ Cons: May be slower due to the overhead of function calls and memory allocation.
* **for...in + push**:
	+ Pros: Can be faster for large arrays since it avoids the overhead of function calls and memory allocation.
	+ Cons: Code is more verbose, less readable, and less expressive.

**Library**

There is no explicit library mentioned in the JSON. However, `Object.keys()` is a built-in JavaScript method that returns an array of property names from an object.

**Special JS Feature/Syntax**

The benchmark uses modern JavaScript features like `map()`, which is supported by most modern browsers and Node.js environments. There are no special JS features or syntax mentioned in the code.

**Alternatives**

If you want to experiment with alternative approaches, here are some options:

* **Lodash**: A popular utility library that provides a `maxBy()` function, similar to `map()`. This could potentially be faster than `Object.keys + map` since it's optimized for performance.
* **Array.prototype.reduce()**: An alternative way to find the maximum value in an array. This approach is more concise than `for...in + push`, but may not be as efficient due to the overhead of function calls and memory allocation.
* **Native Array.prototype.map() with a custom callback**: You can use `map()` with a custom callback function that returns the length of each property name, similar to `Object.keys + map`. This approach avoids the overhead of `Object.keys()` but may not be as readable or concise.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36 Edg/126.0.0.0

Browser/OS: Chrome 126 on Windows

View result in a separate tab

Test name	Executions per second
Object.keys + map	367440.6 Ops/sec
for...in + push	230141.2 Ops/sec

Related benchmarks:

Object.keys + map vs for...in + push (version: 0)

Comparing performance of: Object.keys + map vs for...in + push

Created: 4 months ago by: Registered User

Jump to the latest result

Object.keys + map

for...in + push

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):