Benchmark: for loop vs Array.prototype.map

Tests:

for loop
const numbers = Array(100000).fill(0); for (let i = 0; i < numbers.length; i++) { numbers[i] = i; } const doubled = Array(numbers.length).fill(null); for (let i = 0; i < numbers.length; i++) { doubled[i] = numbers[i] * 2; }
Array.prototype.map
const numbers = Array(100000).fill(0); for (let i = 0; i < numbers.length; i++) { numbers[i] = i; } const doubled = numbers.map((x) => x * 2);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
Array.prototype.map

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
for loop	1189.6 Ops/sec
Array.prototype.map	790.2 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark being conducted is a performance comparison between two JavaScript methods for processing arrays: a traditional `for` loop and the `Array.prototype.map` method. Below is a detailed breakdown of the benchmark, including the options being compared, their pros and cons, and other considerations.

### Options Compared:

1. **For Loop**
   - **Test Name**: "for loop"
   - **Benchmark Definition**:
     ```javascript
     const numbers = Array(100000).fill(0);
     for (let i = 0; i < numbers.length; i++) {
       numbers[i] = i;
     }
     const doubled = Array(numbers.length).fill(null);
     for (let i = 0; i < numbers.length; i++) {
       doubled[i] = numbers[i] * 2;
     }
     ```
   - **Execution Per Second**: 1189.64

2. **Array.prototype.map**
   - **Test Name**: "Array.prototype.map"
   - **Benchmark Definition**:
     ```javascript
     const numbers = Array(100000).fill(0);
     for (let i = 0; i < numbers.length; i++) {
       numbers[i] = i;
     }
     const doubled = numbers.map((x) => x * 2);
     ```
   - **Execution Per Second**: 790.17

### Pros and Cons:

#### For Loop
- **Pros**:
  - **Performance**: The `for` loop executes faster in this benchmark, yielding higher executions per second. This is especially visible in the doubling process.
  - **Control**: Offers more control over the iteration process, allowing for custom logic (e.g., skipping indexes, conditional processing).

- **Cons**:
  - **Verbosity**: Requires more code to achieve the same result as `map`, increasing potential for bugs if the loop is complex.
  - **Readability**: Can be harder to read, especially for complex operations, compared to more declarative methods.

#### Array.prototype.map
- **Pros**:
  - **Readability**: The `map` method is more declarative and concise, making the intention clearer when transforming the array’s values.
  - **Functional Programming Style**: Encourages a functional programming approach, which can lead to fewer side effects and bugs.

- **Cons**:
  - **Performance**: Slower in this case, which can be an important factor in scenarios where performance is critical (e.g., large datasets).
  - **Overhead**: Involves a bit more computational overhead because of the internal function call and context switching that occurs within the `map` function.

### Other Considerations:
- **Result Validity**: It's important to note that performance can vary based on the size of the datasets and the environment in which the code runs (e.g., browser version, hardware specifications).
- **Optimization and JIT**: JavaScript engines use Just-In-Time (JIT) compilation, which can optimize loops and array methods differently based on usage patterns, making the results in different contexts potentially variable.

### Alternatives:
- Other alternatives for array transformation include:
  - **Array.prototype.forEach**: This method is similar to `map` but does not return a new array, making it unsuitable when you want to transform data.
  - **Reduce**: `Array.prototype.reduce` can also be used for more complex transformations and aggregations but has a steeper learning curve and can be overkill for simple tasks.
  - **Typed Arrays**: For numerical processing, JavaScript offers typed arrays (e.g., `Float32Array`), which may offer performance improvements in certain cases.

In conclusion, both the `for` loop and `Array.prototype.map` have their respective merits and drawbacks. The choice between them often depends on the specific requirements of the task at hand, including performance needs, code clarity, and maintainability.

Related benchmarks:

for loop vs Array.prototype.map (version: 1)

Comparing performance of: for loop vs Array.prototype.map

Created: one month ago by: Guest

Jump to the latest result

for loop

Array.prototype.map

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):