Benchmark: String accumulation with forEach vs. map+join vs. reduce

Script Preparation code:

var property = "justify-content";
var value = ["space-around", "space-evenly"];

function normalizeDeclaration(property, value) {
	return property + ":" + value;
}

Tests:

map+join
var result = value .map((fallbackValue) => normalizeDeclaration(property, fallbackValue)) .join(";");
forEach
var cssText = ""; value.forEach((fallbackValue) => { cssText += "" + normalizeDeclaration(property, fallbackValue); }); var result = cssText.slice(1);
reduce
var result = value .reduce((accumulator, fallbackValue) => accumulator + ";" + fallbackValue);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map+join
forEach
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36

Browser/OS: Chrome 84 on Mac OS X 10.15.6

View result in a separate tab

Test name	Executions per second
map+join	1711793.1 Ops/sec
forEach	1906277.9 Ops/sec
reduce	9827996.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark is designed to measure the performance of three different approaches for accumulating strings in JavaScript:

1. **map() + join()**: This approach uses the Array.prototype.map() method to transform each element in the `value` array, then concatenates the resulting values using the String.prototype.join() method.
2. **forEach()**: This approach uses the Array.prototype.forEach() method to iterate over the elements of the `value` array and concatenate them to a string using template literals (e.g., `+ property + ": " + fallbackValue;`).
3. **reduce()**: This approach uses the Array.prototype.reduce() method to accumulate the strings from the `value` array.

**Options Compared**

The benchmark compares these three approaches in terms of performance, which is measured by the number of executions per second (ExecutionsPerSecond).

**Pros and Cons of Each Approach**

1. **map() + join()**: This approach is concise and easy to read. However, it may not be as efficient as other approaches since it creates an intermediate array and then concatenates its elements.
2. **forEach()**: This approach uses template literals, which can make the code more readable and expressive. However, it may have performance overhead due to the creation of temporary strings.
3. **reduce()**: This approach is often preferred in functional programming languages like JavaScript because it's concise and avoids the need for explicit loops. However, it may not be as efficient as other approaches since it creates an accumulator object.

**Library and Purpose**

There are no external libraries used in this benchmark.

**Special JS Features or Syntax**

The benchmark uses template literals (e.g., `+ property + ": " + fallbackValue;`) which is a feature introduced in ECMAScript 2015. This allows for more expressive string interpolation without the need for concatenation operators.

**Other Alternatives**

If you want to explore other approaches, here are some alternatives:

* Using a library like jQuery's `.map()` and `.join()` methods or Lodash's `_each` and `_join` functions.
* Using a different data structure, such as an array of strings instead of an array of values.
* Optimizing the code by using techniques like caching, memoization, or parallel processing.

In general, the choice of approach depends on the specific use case, performance requirements, and personal preference. The benchmark provides a useful starting point for comparing different approaches and identifying potential bottlenecks in your own code.

Related benchmarks:

String accumulation with forEach vs. map+join vs. reduce (version: 0)

Comparing performance of: map+join vs forEach vs reduce

Created: 4 years ago by: Guest

Jump to the latest result

map+join

forEach

reduce

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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