Benchmark: for vs foreach vs for..of

Script Preparation code:

var array = new Array(1000);

Tests:

for
for (var i = 0; i < array.length; i++) { let a = array[i]; a++; }
foreach
array.forEach(function(i) { let a = array[i]; a++; });
some
array.some(function(i) { let a = array[i]; a++; });
for..of
for (var i of array) { let a = array[i]; a++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
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):

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

**Benchmark Definition**

The benchmark aims to compare the performance of three different loop constructs in JavaScript:

1. Traditional `for` loop (`for (var i = 0; i < array.length; i++)`)
2. `forEach` method loop (`array.forEach(function(i) { let a = array[i]; a++; });`)
3. `for...of` loop (`for (var i of array) { let a = array[i]; a++; };`)

**Loop Options Comparison**

The pros and cons of each approach are:

1. **Traditional `for` loop**:
	* Pros: Direct control over the iteration, no additional library dependencies.
	* Cons: Can be verbose and error-prone, especially for complex loops.
2. **`forEach` method loop**:
	* Pros: Concise and readable syntax, fewer potential errors compared to traditional `for`.
	* Cons: May incur a performance overhead due to the method call, and it's not as flexible as traditional `for`.
3. **`for...of` loop**:
	* Pros: Very concise and expressive syntax, efficient iteration.
	* Cons: Limited control over the iteration, may not work with arrays that have non-numeric indices.

**Library Usage**

The test case uses the `Array.prototype.forEach()` method from the ECMAScript standard. This library is built-in to most modern JavaScript engines and provides a concise way to iterate over array elements.

**Special JS Features/Syntax**

The test case utilizes the `for...of` loop, which was introduced in ECMAScript 2015 (ES6). This syntax allows for more expressive and concise iteration over arrays and other iterable objects. The traditional `for` loop also uses this feature implicitly when using a `for` declaration with an array.

**Alternative Approaches**

Other alternatives to these three approaches could include:

1. **`map()` method**: While not a loop construct per se, the `map()` method can be used to iterate over arrays and transform each element. However, it may incur additional overhead compared to loops.
2. **Recursion**: Recursive functions can be used to iterate over array elements, but this approach is generally less efficient and more prone to stack overflow errors.
3. **`reduce()` method**: Similar to `map()`, the `reduce()` method can be used to accumulate values from an iterable sequence. However, it's typically used for aggregation or reducing arrays to a single value.

These alternatives are not as straightforward to compare performance-wise to traditional loops, but they offer different use cases and benefits in certain scenarios.

Related benchmarks:

for vs foreach vs for..of (version: 0)

Compare loop performance

Comparing performance of: for vs foreach vs some vs for..of

Created: 4 years ago by: Guest

Jump to the latest result

for

foreach

some

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):