Benchmark: Compare performance of for..of and forEach with filter, v3

Script Preparation code:

var array = [];
[new Array(100000)].forEach(function(t) {
    var newObj = {
        id: t,
        name: `some name ${t}`,
        mod: t % 2,
    }
    array.push(newObj);
});

Tests:

foreach and filter
array.filter(function(a) { return a.mod}).forEach(function(a) {a});
for of
for (var item of array) { if (item.mod) { item; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach and filter
for of

Fastest: N/A

Slowest: N/A

Latest 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 benchmark is designed to compare the performance of two JavaScript iteration methods:

1. `for...of` loop with filtering using the `Array.prototype.filter()` method.
2. Traditional `forEach` loop with filtering using the same `Array.prototype.filter()` method.

**Options compared:**

In this case, only two options are being compared: `foreach and filter` and `for of`. Both methods involve iterating over an array and filtering out elements based on a condition (`item.mod`).

**Pros and Cons:**

1. **Traditional `forEach` loop with filtering**: This approach can be useful when you need to perform some side effects (e.g., logging or updating the DOM) during iteration. However, it can lead to slower performance due to the overhead of calling the callback function for each element.
2. **`for...of` loop with filtering**: This approach is generally faster and more efficient than the traditional `forEach` loop, especially when filtering large arrays. It also eliminates the need for manual indexing and bounds checking.

**Other considerations:**

* The use of `Array.prototype.filter()` as a common ground for both options might not be representative of real-world scenarios where filtering is performed independently.
* The condition used for filtering (`item.mod`) is simple and consistent, but other conditions might have different performance implications.
* There are no explicit checks for bounds checking or index access issues in either option.

**Library and purpose:**

None mentioned in the provided benchmark definition.

**Special JS feature or syntax:**

The `for...of` loop uses a new iteration method introduced in ECMAScript 2015 (ES6). It allows iterating over arrays, iterables, and other data structures without explicit indexing or manual bounds checking. The traditional `forEach` loop is also supported.

**Other alternatives:**

In general, when working with arrays, you might consider using other methods like:

* `Array.prototype.forEach()`: A simpler alternative to the traditional `for...of` loop.
* `Array.prototype.map()` and `Array.prototype.reduce()`: Which can often replace manual iteration and filtering operations.
* `Set` or `Map` data structures: When working with unique values or key-value pairs, respectively.

Keep in mind that the choice of iteration method depends on the specific use case, performance requirements, and personal preference.

Related benchmarks:

Compare performance of for..of and forEach with filter, v3 (version: 2)

Comparing performance of: foreach and filter vs for of

Created: 4 years ago by: Registered User

Jump to the latest result

foreach and filter

for of

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):