Benchmark: object iteration methods kate and waller edition

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

window.obj = Object.fromEntries(
  new Array(10000)
  	.fill(null)
  	.map(
      _none => [
        Math.random().toString(36).substr(2, 5), 
        _.random(20)
      ]
    )
)

Tests:

For of
let res = {} for (let [key, value] of Object.entries(obj)) { res[key] = value * 2 }
forEachKey
Object.keys(obj).forEach((key) => { obj[key] = obj[key] * 2 })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For of
forEachKey

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

**Benchmark Definition:**

The provided `Script Preparation Code` creates an object `obj` with 10,000 key-value pairs, where each value is a random string followed by a random integer between 0 and 19. The `Html Preparation Code` includes the Lodash library, which provides utility functions for JavaScript.

**Test Cases:**

There are two test cases:

1. **For of**: This benchmark uses the `for...of` loop to iterate over the key-value pairs of the `obj` object. In each iteration, it calculates a new value by multiplying the original value with 2.
2. **forEachKey**: This benchmark uses the `forEach()` method on the `Object.keys()` array of the `obj` object. It iterates over the keys of the object and updates the corresponding values by multiplying them with 2.

**Options Compared:**

The test cases compare two different approaches to iterate over the key-value pairs of an object:

1. **For of**: This method uses a loop that is native to JavaScript, which may provide better performance since it doesn't require additional function calls or data structures.
2. **forEachKey**: This method uses a callback function with `Object.keys()` and `forEach()`, which may incur additional overhead due to the extra function call and data structure.

**Pros and Cons:**

Pros of each approach:

* **For of**: Faster execution, as it's a native loop that doesn't require additional function calls or data structures.
* **forEachKey**: More concise and expressive code, as it uses a familiar method for iterating over arrays.

Cons of each approach:

* **For of**: May not work as expected if the object is modified during iteration (e.g., by using `delete` to remove properties).
* **forEachKey**: May be slower due to additional function calls and data structures.

**Library:**

The Lodash library is used in the benchmark definition. It provides utility functions for JavaScript, including `Object.fromEntries()`, which helps create objects from arrays of key-value pairs.

**Special JS Feature/Syntax:**

No special features or syntax are used in this benchmark.

**Other Alternatives:**

Other alternatives to iterate over an object's properties could include:

1. **`for...in` loop**: This method iterates over the object's property names (i.e., keys). It may not provide the same performance as `for of`, but it can be useful in certain situations.
2. **`Array.prototype.forEach()` with a custom iterator**: You could create a custom iterator using `Set` or other data structures to iterate over an object's properties.

Keep in mind that these alternatives may have different trade-offs and requirements compared to the tested approaches.

**Benchmark Result Interpretation:**

The benchmark result shows the number of executions per second for each test case. A higher value indicates better performance. In this case, the `For of` loop appears to be faster than the `forEachKey` approach.

Related benchmarks:

object iteration methods kate and waller edition (version: 0)

Comparing performance of: For of vs forEachKey

Created: 4 years ago by: Guest

Jump to the latest result

For of

forEachKey

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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