Benchmark: test forin vs keys+foreach+for

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

  let temp = {
  "surname": "Verdi",
  "name": "Giovanni",
  "cfPiva": "VRDGVN90C12E567Z",
  "plate": "IJ789KL",
  "birthDate": "1990-10-20",
  "proviceBirth": "Torino",
  "cityBirth": "Torino",
  "proviceResidence": "Torino",
  "cityResidence": "Torino",
  "company": "LMN Srl",
  "mainRole": "Ingegnere",
  "roles": "Sviluppatore, Progettista",
  "injuries": "Nessuno"
};let imports={};

Tests:

for in test
for (const key in temp) { imports[key] = "true"; }
keys+foreach
Object.keys(temp).forEach(key => { imports[key] = "true"; });
test for
let array = Object.keys(temp); for (let index = 0; index < array.length; index++) { imports[array[i]] = "true"; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for in test
keys+foreach
test for

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 14 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
for in test	3546726.8 Ops/sec
keys+foreach	3250035.8 Ops/sec
test for	10595269.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 14 days ago):

LLMs can make mistakes. Check important info.

The benchmark you provided tests the performance of three different approaches to iterating over an object's properties in JavaScript. The testing compares a traditional `for...in` loop, the use of `Object.keys()` combined with `forEach`, and a `for` loop with an array of keys derived from `Object.keys()`.

### Approaches Compared

1. **`for...in` loop**:
    - **Snippet**: 
      ```javascript
      for (const key in temp) {
          imports[key] = "true";
      }
      ```
    - **Description**: This syntax is used to iterate over all enumerable properties of an object. 
    - **Pros**:
        - Directly traverses the object without needing additional methods.
        - Easy to write and understand.
    - **Cons**:
        - It iterates over all enumerable properties, including inherited ones, which may introduce unintended behavior if the object has inherited properties or if the prototype chain has properties.
        - Performance can be slower compared to alternatives in certain cases due to the additional overhead of checking for properties on the prototype chain.

2. **`Object.keys()` with `forEach`**:
    - **Snippet**: 
      ```javascript
      Object.keys(temp).forEach(key => {
          imports[key] = "true";
      });
      ```
    - **Description**: This method retrieves the object's own enumerable property names as an array, and then `forEach` iterates over that array.
    - **Pros**:
        - Focuses only on the object's own properties (not inherited ones), which can prevent unexpected behavior.
        - `forEach` provides a functional programming style, often seen as cleaner.
    - **Cons**:
        - Slightly higher overhead due to the creation of an additional array (the keys array) and the function call overhead associated with `forEach`.

3. **`for` loop with `Object.keys()`**:
    - **Snippet**: 
      ```javascript
      let array = Object.keys(temp);
      for (let index = 0; index < array.length; index++) {
          imports[array[index]] = "true";
      }
      ```
    - **Description**: This approach is a classic `for` loop that employs an array of keys generated by `Object.keys()`.
    - **Pros**:
        - Similar to the `keys + forEach` method, it only accesses the object's own properties.
        - Offers better performance than `forEach` due to reduced overhead from avoiding the function call overhead.
    - **Cons**:
        - Slightly more verbose than using `forEach`.
        - Requires manual handling of array element access using the index.

### Benchmark Results Summary

From the benchmark results:

- **Test Name: `test for `**
  - **Executions Per Second**: 10,595,269.0 (Fastest)
  
- **Test Name: `for in test`**
  - **Executions Per Second**: 3,546,726.75

- **Test Name: `keys+foreach`**
  - **Executions Per Second**: 3,250,035.75

### Performance Observations

1. The **`for` loop** with `Object.keys()` is the fastest among the three approaches in this benchmark. This may be due to its straightforward access pattern and the avoidance of function call overhead.

2. The **`for...in` loop** is the slowest, likely because of the extra overhead introduced by checking for inherited properties.

3. The **`Object.keys() + forEach`** method performs moderately, indicating that while it is clear and concise, it does incur a slight performance penalty compared to a plain loop.

### Alternatives

- **Map Structure**: In many cases, employing a `Map` in place of a plain object can yield better performance and clearer semantics, especially when working extensively with key-value pairs.
- **`for...of` with `Object.entries()`**: Another approach could be using a `for...of` loop in conjunction with `Object.entries()` that gives both key and value pairs directly. This can lead to a different control structure depending on your use case.
  
In summary, the benchmark provides insight into different iteration methods over object properties, highlighting their performance characteristics and helping guide developers to make informed decisions based on their specific requirements.

Related benchmarks:

test forin vs keys+foreach+for (version: 1)

Comparing performance of: for in test vs keys+foreach vs test for

Created: 14 days ago by: Guest

Jump to the latest result

for in test

keys+foreach

test for

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 14 days ago):