Benchmark: compare for loop with filter

Script Preparation code:

var objectSize = 1000000;
var iterations = 20;

var anyStringObject = {};

var start = 0;
var end = 0;

for (var i = 0; i < objectSize; i++) {
  anyStringObject[`key${i}`] = `val${i}`;
}

var condition = (key) => true;

Tests:

for loop
for (var i = 0; i < iterations; i++) { var objectKeys = []; var keys = Object.keys(anyStringObject); var length = keys.length; for (var index = 0; index < length; index++) { if (condition(keys[index])) { objectKeys.push(keys[index]); } } }
filter
for (var i = 0; i < iterations; i++) { var keys = Object.keys(anyStringObject); keys.filter((key) => condition(key)); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
filter

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

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Let's dive into the explanation of this benchmark.

**What is being tested?**

The benchmark compares two different approaches to filter objects in JavaScript:

1. Using a traditional `for` loop
2. Using the `filter()` method on an array created from the object keys

**Options compared:**

* **For Loop**: A classic approach where you iterate over the object's keys using a `for` loop, and then conditionally include or exclude each key based on the specified criteria.
* **Filter Method**: A more modern approach that leverages the `filter()` method to create an array of keys from the object, and then applies the conditional logic to each key.

**Pros/Cons:**

* **For Loop**:
	+ Pros:
		- Well-known and widely supported by all browsers
		- Can be more readable and easier to debug in certain scenarios
	+ Cons:
		- May require more code and explicit iteration over the object keys
		- Can be slower for large objects or complex conditions
* **Filter Method**:
	+ Pros:
		- More concise and expressive code
		- Often faster for large objects or complex conditions
	+ Cons:
		- May not be supported in older browsers (pre-Es6)
		- Can be less readable and harder to debug for beginners

**Considerations:**

* **Browser Support**: As mentioned earlier, the `filter()` method is an Es6 feature that may not be supported in older browsers. If you need to support ancient browsers, the `for` loop approach might be a safer choice.
* **Performance**: While the benchmark results show a slight difference between the two approaches, it's essential to note that the performance gap may not be significant for small objects or simple conditions.

**Library and special JS features:**

None in this specific benchmark. No external libraries are used, and no special JavaScript features or syntax are employed beyond what's typically supported by modern browsers.

**Alternatives:**

If you need to filter an object with a large number of keys, consider using the following alternatives:

* **Map()**: Similar to `filter()`, but returns a new map instead of an array.
* **Object.keys().reduce()**: A more functional approach that uses `reduce()` to transform the key-value pairs into a filtered result.

Keep in mind that while these alternatives can be effective, they may also require some learning and experimentation to master.

Related benchmarks:

compare for loop with filter (version: 0)

Comparing performance of: for loop vs filter

Created: 4 years ago by: Guest

Jump to the latest result

for loop

filter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):