Benchmark: for loop vs array.forEach - on regular looping use

Tests:

for loop
for (let i = 1; i <= 1000; i++) { console.log(i); }
array.forEach
[...Array(1000)].forEach((val,i,arr) => console.log(i+1));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
array.forEach

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 20 days ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the JSON compares two methods for iterating through a sequence of numbers from 1 to 1000 in JavaScript: a traditional `for` loop and the `Array.prototype.forEach` method. This comparison is helpful for understanding performance differences between commonly used iteration techniques and can aid in making more informed decisions about which to use in different scenarios.

### Test Cases

1. **For Loop**:
   ```javascript
   for (let i = 1; i <= 1000; i++) {
       console.log(i);
   }
   ```
   - **Test Name**: `for loop`
   - This method uses a traditional `for` loop with an index variable `i` that increments from 1 to 1000. The `console.log(i)` function outputs the current index during each iteration.

2. **Array.forEach**:
   ```javascript
   [...Array(1000)].forEach((val,i,arr) => console.log(i+1));
   ```
   - **Test Name**: `array.forEach`
   - Here, an array of size 1000 is created using the spread operator `[...]` with `Array(1000)`. The `forEach` method iterates over this array, executing the provided callback function, which logs the index plus one (`i + 1`), corresponding to the numbers 1 to 1000.

### Performance Results

The benchmark results indicate the number of executions per second for each method:
- **For Loop**: Approximately **752.39 executions per second**.
- **Array.forEach**: Approximately **619.37 executions per second**.

### Pros and Cons

#### For Loop:
- **Pros**:
  - Generally faster than `Array.forEach`, as shown by the benchmark.
  - Provides more control over the iteration process (e.g., easy to modify increment steps, access current index directly).
  - Can directly manipulate variables outside its scope, making it more flexible for complex logic.

- **Cons**:
  - More verbose and potentially error-prone if not handled carefully (e.g., off-by-one errors).
  - Slightly more difficult to read for those unfamiliar with traditional looping constructs.

#### Array.forEach:
- **Pros**:
  - More declarative and arguably easier to read for those comfortable with functional programming styles.
  - Automatically handles iteration without manual index management, reducing potential errors.
  - Encourages a functional approach to programming, which can lead to more maintainable code in certain contexts.

- **Cons**:
  - Slower performance compared to `for` loops, as the benchmark suggests; this can be a significant factor in performance-critical applications.
  - Cannot be easily exited from (you can’t use `break` or `continue`).
  - Slightly more overhead due to the function call for each iteration, which may impact performance, especially in larger data sets.

### Other Considerations
- The choice between these two methods depends heavily on the specific use case. For performance-sensitive tasks where speed is critical, the `for` loop is often preferred. For scenarios where code readability and maintainability are paramount, or when dealing with functional constructs, `Array.forEach` might be the better choice.

### Alternatives
1. **For...of Loop**: Can be used for iterating over iterable objects. It is less verbose and may provide better readability but may have performance characteristics similar to `Array.forEach`.
   ```javascript
   for (const number of Array.from({ length: 1000 }, (_, i) => i + 1)) {
       console.log(number);
   }
   ```

2. **While Loop**: Provides flexibility and can be adjusted according to the loop control.
   ```javascript
   let i = 1;
   while (i <= 1000) {
       console.log(i);
       i++;
   }
   ```

3. **Map Method**: For a functional style—though not typically used solely for side effects like logging, it can transform an array and retain the courtesy of chaining.
   ```javascript
   Array.from({ length: 1000 }, (_, i) => i + 1).map(num => console.log(num));
   ```

In summary, this benchmark gives insight into the efficiency of traditional versus more modern JavaScript iteration methods, allowing developers to choose the right tool for their particular application context.

Latest run results:

Run details: (Test run date: 16 days ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Mobile Safari/537.36 EdgA/130.0.0.0

Browser/OS: Chrome Mobile 130 on Android

View result in a separate tab

Test name	Executions per second
for loop	47.0 Ops/sec
array.forEach	46.7 Ops/sec

Related benchmarks:

for loop vs array.forEach - on regular looping use (version: 0)

Comparing performance of: for loop vs array.forEach

Created: 20 days ago by: Guest

Jump to the latest result

for loop

array.forEach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 20 days ago):