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

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

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

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

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

**What is being tested?**

The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net. The main focus of this benchmark is to compare the performance of different iteration methods in JavaScript: Array `forEach()`, traditional `for` loop, `Array.prototype.map()` method, and an arrow function-based `for...of` loop.

**Options compared**

The four options being compared are:

1. **Array `forEach()`**: This method calls a provided callback function once for each element in the array, allowing it to be used as an iterator.
2. **Traditional `for` loop**: A classic loop structure that manually increments a counter and accesses elements of an array using their index.
3. **`Array.prototype.map()` method**: A method that creates a new array with the results of applying a provided function on every element in this array.
4. **Arrow function-based `for...of` loop**: An alternative syntax for iterating over arrays, introduced in ECMAScript 2015 (ES6).

**Pros and Cons**

1. **Array `forEach()`**:
	* Pros: Simple to use, doesn't require manual index management, allows callback functions to perform side effects.
	* Cons: Can lead to performance issues if not optimized correctly, may be slower due to function call overhead.
2. **Traditional `for` loop**:
	* Pros: Direct access to array elements, no additional function call overhead, can be optimized for specific use cases.
	* Cons: More verbose and error-prone compared to other options, requires manual index management, can lead to performance issues if not optimized correctly.
3. **`Array.prototype.map()` method**:
	* Pros: Returns a new array with the results of applying the provided function, allows for concise code, and is often faster than traditional `for` loops due to compiler optimizations.
	* Cons: Can create unnecessary memory allocations, may be slower for large datasets if not optimized correctly, and can lead to performance issues if not used carefully.
4. **Arrow function-based `for...of` loop**:
	* Pros: More concise and readable than traditional `for` loops, allows for the use of arrow functions, and is often faster due to compiler optimizations.
	* Cons: May be less familiar or intuitive to developers without experience with ES6 features.

**Library and syntax**

The provided test cases use the following libraries and syntax:

1. No external library usage.
2. All test cases use native JavaScript features only (no third-party libraries).
3. No special JavaScript features or syntax are used outside of the standard ES6 `for...of` loop introduced in ECMAScript 2015 (ES6).

**Alternatives**

If you're looking for alternative benchmarking tools or approaches, consider the following:

1. **V8 Benchmark Suite**: A widely-used benchmark suite specifically designed to measure JavaScript performance.
2. **JSPerf**: Another popular online benchmarking tool for measuring JavaScript performance.
3. **Benchmarking frameworks**: Consider using specialized frameworks like `benchmark.js` or `fastify-benchmark`, which provide a more structured approach to writing and running benchmarks.

In conclusion, the provided MeasureThat.net benchmark provides a simple and concise way to compare the performance of different iteration methods in JavaScript. By understanding the pros and cons of each option, developers can make informed decisions about which approach best suits their use case.

Related benchmarks:

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

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

Created: 7 years ago by: Guest

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):