Benchmark: Array loop vs foreach vs map vs for..of

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

foreach
arr.forEach(function (item){ someFn(item); })
for
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
map
arr.map(item => someFn(item))
for..of
for (const item of arr) { someFn(item); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
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 dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The provided JSON represents a benchmark that tests four different approaches for iterating over an array in JavaScript:

1. `forEach`
2. Traditional `for` loop
3. `map` method
4. `for...of` loop (introduced in ECMAScript 2015)

Each of these approaches is compared to determine which one is the most efficient.

**Options Compared**

The four options are compared based on their performance, measured by the number of executions per second (`ExecutionsPerSecond`). The option with the highest execution rate is considered the fastest.

**Pros and Cons of Each Approach**

1. **`forEach`**:
	* Pros: Easy to read and maintain, concise syntax.
	* Cons: May be less efficient than other approaches due to its nature of iterating over an array in a single pass.
2. **Traditional `for` loop**:
	* Pros: Control over iteration variables, flexible indexing.
	* Cons: More verbose syntax, can lead to indexing errors if not used carefully.
3. **`map` method**:
	* Pros: Concise and expressive syntax, returns an array of results without modifying the original array.
	* Cons: May be less efficient than other approaches due to its use of a new array and potentially unnecessary function calls.
4. **`for...of` loop** (ECMAScript 2015):
	* Pros: Modern, concise syntax, easy to read and maintain.
	* Cons: Less control over iteration variables compared to traditional `for` loops.

**Library Used**

None of the options explicitly use any libraries in their implementation. However, some modern JavaScript engines may optimize or specialize certain implementations of these approaches.

**Special JS Features/Syntax**

The benchmark uses ECMAScript 2015 features such as:

1. Arrow functions (`=>`)
2. `const` and `let` declarations (used for variable declarations)
3. Template literals (`\r\n`) (used in the "Script Preparation Code")

These features are used to make the code more concise and modern.

**Other Alternatives**

If you're interested in exploring alternative approaches or optimizations, here are a few options:

1. **Regular expressions**: Using regular expressions to iterate over arrays can be an alternative approach.
2. **Native array methods**: Some native array methods, such as `findIndex` or `forEach`, may offer performance benefits depending on the specific use case.
3. **Custom iteration**: Implementing custom iteration mechanisms, such as using a queue or stack data structure, can potentially lead to better performance.

Keep in mind that these alternatives might not be as straightforward or efficient as the options tested in the benchmark.

I hope this explanation helps you understand what's happening behind the scenes of this JavaScript microbenchmark!

Related benchmarks:

Array loop vs foreach vs map vs for..of (version: 0)

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

Created: 3 years ago by: Registered User

Jump to the latest result

foreach

for

map

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):