Benchmark: for loop comparison test

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/lodash/4.16.0/lodash.min.js"></script>

Script Preparation code:

var values = [{a: 30310}, {b: 100303}, {c: 3040494}]

Tests:

lodash.forEach
var count = 0; _.forEach(values, function(v,i) { if (v.a != null) { count++; } });
native
var count = 0; for (var i = 0; i < values.length; i++) { if (values[i].a != null) { count++; } }
ES5 forEach (cannot break;)
var count = 0; values.forEach(function(v,i) { if (v.a != null) { count++; } });
ES5 for-in
var count = 0; for (value in values) { if (value.a != null) { count++; } }
ES6 for-of
var count = 0; for (value of values) { if (value.a != null) { count++; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash.forEach
native
ES5 forEach (cannot break;)
ES5 for-in
ES6 for-of

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):

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Let's break down the benchmark and its test cases.

**Benchmark Purpose**

The goal of this benchmark is to compare the performance of different JavaScript iteration methods: `_lodash.forEach`, native `for` loop, ES5 `forEach`, ES5 `for-in`, and ES6 `for-of`. The benchmark measures how many iterations each method performs in a given amount of time.

**Test Cases**

Each test case corresponds to a specific iteration method:

1. **_lodash.forEach`:** Lodash's implementation of the `forEach` function, which iterates over an array using a callback function.
2. **Native "for" loop**: A traditional `for` loop that manually increments an index variable to iterate over the elements of an array.
3. **ES5 "forEach" (cannot break)**: An ES5 implementation of `forEach`, which uses the `break` statement inside the callback function, but still iterates correctly due to its semantic nature.
4. **ES5 "for-in"`: A traditional `for...in` loop that iterates over the properties of an object using a variable as the property name.
5. **ES6 "for-of"`: An ES6 implementation of `for...of`, which uses a specific syntax to iterate over an array or other iterable.

**Options Compared**

The benchmark compares the performance of each iteration method:

* **Performance**: How many iterations each method performs per second (ExecutionsPerSecond).
* **Implementation differences**: The use of callbacks, manual index management, and semantic features like `break` in the callback function.

**Pros and Cons of Each Approach**

Here's a brief summary:

1. **_lodash.forEach`**:
	* Pros: High-level abstraction, easy to use, well-tested.
	* Cons: May introduce overhead due to its implementation complexity.
2. **Native "for" loop**:
	* Pros: Low-level control, efficient execution.
	* Cons: Requires manual index management and error handling.
3. **ES5 "forEach" (cannot break)**:
	* Pros: Still an iterative method with low overhead.
	* Cons: The `break` statement inside the callback function can be confusing.
4. **ES5 "for-in"`:
	* Pros: Traditional, familiar syntax for experienced developers.
	* Cons: May be slower and less efficient due to its object-oriented nature.
5. **ES6 "for-of"`:
	* Pros: Modern syntax, efficient execution.
	* Cons: Requires ES6 support, which may not be available in all browsers.

**Library Usage**

The benchmark uses Lodash's implementation of `forEach`, which provides a convenient and high-level abstraction for iterating over arrays.

**Special JS Features or Syntax**

This benchmark does not use any special JavaScript features or syntax beyond the standard iteration methods. However, it does use ES6 features like `for-of` and Lodash's `_`.

**Alternatives**

Other alternatives to these iteration methods include:

* Using a library like `forEach` from a different implementation (e.g., vanilla JavaScript).
* Implementing your own custom iteration method using recursion or other techniques.
* Using parallel processing or async/await for I/O-bound operations.

Note that the choice of iteration method depends on the specific use case and performance requirements.

Related benchmarks:

for loop comparison test (version: 0)

Comparing performance of: lodash.forEach vs native vs ES5 forEach (cannot break;) vs ES5 for-in vs ES6 for-of

Created: 4 years ago by: Guest

Jump to the latest result

lodash.forEach

native

ES5 forEach (cannot break;)

ES5 for-in

ES6 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):