Benchmark: Object.keys.length vs sum with for a

Script Preparation code:

window.obj = {};
window.arr = [];

for (var i = 0, len = 100; i < len; i++) {
  obj['key' + i] = 'value' + i;
  arr.push('value' + i)
}

Tests:

_.isEmpty
let len = window.arr.lenght > 0;
Object.keys().length
let len = Object.keys(window.obj).length > 0;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
_.isEmpty
Object.keys().length

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:88.0) Gecko/20100101 Firefox/88.0

Browser/OS: Firefox 88 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
_.isEmpty	7040638.0 Ops/sec
Object.keys().length	1418510.6 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark JSON, explaining what's being tested, and discuss the pros and cons of each approach.

**Benchmark Definition:**

The first benchmark defines a JavaScript microbenchmark that measures the performance difference between two approaches:

1. `Object.keys().length` vs
2. Using a manual loop to get the length of an object's keys (`for (var i = 0, len = 100; i < len; i++) { ... }`)

**Options Compared:**

Both methods are used to retrieve the number of key-value pairs in an object:

* `Object.keys().length`: This method returns the length of an array-like property named "keys" on an object. It's a built-in method that provides a concise way to get the count.
* Manual loop: The benchmark uses a traditional loop to iterate over each key-value pair and increments a counter variable (`len`) for each iteration.

**Pros and Cons:**

**Object.keys().length:**

Pros:

1. Concise and easy to read.
2. Built-in method, so it's likely optimized by the JavaScript engine.

Cons:

1. May not work correctly in older browsers or environments that don't support this feature.
2. Performance might be slower due to the overhead of calling a built-in function.

**Manual Loop:**

Pros:

1. Portable across all browsers and environments (since it doesn't rely on any specific features).
2. Control over performance-critical parts, as you can optimize the loop itself.

Cons:

1. More verbose and harder to read.
2. Requires manual iteration over each key-value pair, which might lead to errors if not implemented correctly.

**Library Used:**

None is explicitly mentioned in this benchmark definition. However, it's likely that other benchmarks might use libraries like Benchmark.js or micro-benchmarking frameworks.

**Special JS Feature or Syntax:**

There are no special features or syntaxes mentioned in this benchmark definition.

**Other Alternatives:**

If you need to measure the performance of different ways to retrieve an object's key count, some alternative methods could be:

1. Using `for...in` loop: This method iterates over each property (including keys) in an object using a traditional loop.
2. Using `Array.from()` and `map()`: Convert the object's keys into an array and then use `length` to get the count.
3. Using `JSON.stringify()` with `Object.keys()`: Similar to `Object.keys().length`, but uses `JSON.stringify()` to iterate over the object's properties.

Keep in mind that each alternative has its own trade-offs, and the best approach depends on your specific requirements and constraints.

Related benchmarks:

Object.keys.length vs sum with for a (version: 0)

Comparing performance of: _.isEmpty vs Object.keys().length

Created: 3 years ago by: Guest

Jump to the latest result

_.isEmpty

Object.keys().length

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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