Benchmark: Array loop vs foreach vs map vs while vs some

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

foreach
arr.forEach(function (item){ someFn(item); })
for
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
map
arr.map(item => someFn(item))
while
let i = 0, len = arr.length; while (i<len) { someFn(arr[i]); i++; }
some
arr.some(item => someFn(item))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
while
some

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 dive into the world of JavaScript microbenchmarks.

**Benchmark Overview**

The provided JSON represents a benchmark that tests the performance of different ways to iterate over an array in JavaScript: `forEach`, `for`, `map`, and `while`. The test case uses a custom function `someFn` to perform some calculations on each element of the array.

**Options Compared**

Here's what's being compared:

1. `forEach`: This method iterates over the array, executing the provided callback function for each element.
2. `for`: A traditional loop that iterates over the array using an index variable.
3. `map`: This method returns a new array with the results of applying the provided callback function to each element in the original array.
4. `while`: A loop that continues as long as a certain condition is true, incrementing an index variable until it reaches the end of the array.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

1. **forEach**: Pros:
	* Concise and easy to read.
	* Eliminates the need for manual indexing.
	Cons:
	* May incur additional overhead due to callback function creation.
2. `for`: Pros:
	* Fast and efficient, with minimal overhead.
	* Allows for fine-grained control over iteration.
Cons:
	* Requires manual indexing, which can lead to errors.
3. `map`: Pros:
	* Returns a new array, allowing for easier iteration and data transformation.
	* Can be more expressive and readable than traditional loops.
Cons:
	* May incur additional overhead due to array creation and element transformation.
4. `while`: Pros:
	* Allows for fine-grained control over iteration.
	Cons:
	* Requires manual indexing and can lead to errors.

**Library Usage**

The test case uses the built-in `some` method, which returns a boolean value indicating whether at least one element in the array satisfies the provided condition. The `someFn` function is called for each element in the array, but it's not strictly necessary to include this in the benchmark, as the `some` method already performs the necessary calculations.

**Special JavaScript Features**

There are no special JavaScript features or syntax mentioned in the benchmark definition or individual test cases. However, it's worth noting that modern JavaScript engines often have optimized implementations for certain tasks, such as array iteration and caching.

**Other Alternatives**

If you wanted to include additional alternatives in the benchmark, here are some options:

1. `reduce`: Similar to `map`, but returns a single value instead of an array.
2. `every`: Returns a boolean value indicating whether all elements in the array satisfy the provided condition.
3. Iterators or generators: These provide a more functional programming-style approach to iteration, allowing for concise and expressive code.

However, these alternatives may not be directly applicable to this specific benchmark, as they often require additional setup and context.

Related benchmarks:

Array loop vs foreach vs map vs while vs some (version: 0)

Comparing performance of: foreach vs for vs map vs while vs some

Created: 4 years ago by: Guest

Jump to the latest result

foreach

for

map

while

some

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):