Benchmark: forEach vs filter

Script Preparation code:

var filters = [{
    id: 'foo',
    value: 'hello',
}, {
    id: 'bar',
    value: 'world'
}, ]

var items = [{
    foo: 'hello',
    bar: 'world',
}, {
    foo: 'hello',
    bar: '',
}, {
    foo: '',
    bar: 'world'
}, {
    foo: 'foo',
    bar: 'bar'
}, ]

Tests:

forEach
var newItems = [...items] filters.forEach(filter => { newItems = newItems.filter(item => item[filter.id].includes(filter.value)) });
filter
var newItems = items.filter(item => filters.filter(filter => item[filter.id].includes(filter.value)).length)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
filter

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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Let's break down the provided benchmark and explain what is being tested.

**Benchmark Definition**

The benchmark is designed to compare the performance of two different approaches: `forEach` and `filter`. The benchmark involves creating an array of items, filtering it using both methods, and measuring the execution time.

**Options Compared**

Two options are compared:

1. **forEach**: This method iterates over the filters array and applies each filter to the items array in sequence.
2. **filter**: This method creates a new array with only the items that pass the test implemented by the provided function.

**Pros and Cons of Each Approach**

### forEach

* Pros:
	+ Can be more flexible, as it allows for arbitrary filtering logic.
	+ May perform better if the number of filters is small compared to the number of items.
* Cons:
	+ Requires an explicit loop, which can be slower than a single filter operation.
	+ May require additional memory allocation for the new filtered array.

### filter

* Pros:
	+ More concise and expressive code, as it uses a single function reference.
	+ Typically faster, as it avoids the overhead of an explicit loop.
* Cons:
	+ May perform worse if the number of filters is large compared to the number of items.
	+ Requires that each filter has a unique `id` property.

**Library and Syntax**

In this benchmark, there is no specific library used. However, both methods rely on JavaScript's built-in array methods (`forEach` and `filter`). The syntax for these methods is well-documented and widely supported across different browsers and environments.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. Both methods use standard JavaScript syntax and do not rely on any advanced or experimental features.

**Other Alternatives**

If you wanted to write an alternative implementation for this benchmark, you could consider using:

* `reduce()`: Instead of `forEach`, you could use `reduce()` with a callback function to accumulate the filtered items.
* A custom loop: If you want to avoid using built-in array methods, you could write a custom loop using `for` or `while` statements to iterate over the filters and apply each filter to the items.

Keep in mind that these alternatives would likely have different performance characteristics and may not be as concise or expressive as the original implementation.

Related benchmarks:

forEach vs filter (version: 0)

Comparing performance of: forEach vs filter

Created: 5 years ago by: Guest

Jump to the latest result

forEach

filter

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):