Benchmark: String accumulation using 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:

forEach
var cssText = ""; value.forEach((fallbackValue) => { cssText += "" + normalizeDeclaration(property, fallbackValue); }); var result = cssText.slice(1);
map+join
var result = value .map((fallbackValue) => normalizeDeclaration(property, fallbackValue)) .join(";");
reduce
var result = value.reduce( (accumulator, fallbackValue) => accumulator + ";" + normalizeDeclaration(property, fallbackValue), normalizeDeclaration(property, value[0]) );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
map+join
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:134.0) Gecko/20100101 Firefox/134.0

Browser/OS: Firefox 134 on Windows

View result in a separate tab

Test name	Executions per second
forEach	17499306.0 Ops/sec
map+join	1645113.1 Ops/sec
reduce	9403693.0 Ops/sec

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 explain what's being tested.

**Benchmark Definition**

The benchmark is defined by two JSON objects: one for the overall benchmark and one for individual test cases.

1. The overall benchmark defines:
	* A script preparation code that sets up a variable `property` with value `"justify-content"` and an array `value` containing two strings: `"space-around"` and `"space-evenly"`. It also defines a function `normalizeDeclaration` that takes `property` and a `fallbackValue` as arguments.
	* An HTML preparation code (empty in this case)
2. The individual test cases define three different ways to accumulate strings:
	* `forEach`: uses the `forEach` method to iterate over the `value` array, concatenating each string with the `normalizeDeclaration` function.
	* `map+join`: uses the `map` method to transform each element in the `value` array into a string using `normalizeDeclaration`, and then joins these strings together with a separator (in this case, an empty string).
	* `reduce`: uses the `reduce` method to accumulate the concatenated strings.

**Comparison**

The three approaches are being compared for their performance:

1. **forEach**: Iterates over each element in the array using `forEach`, concatenating it with the `normalizeDeclaration` function.
2. **map+join**: Transforms each element into a string and then joins them together, potentially consuming more memory due to the intermediate string creation.
3. **reduce**: Accumulates the concatenated strings using a single loop, which might be faster but also increases the risk of overflowing the accumulator.

**Pros and Cons**

* **forEach**:
	+ Pros: Simple, easy to understand, and might be less memory-intensive due to not creating an intermediate string.
	+ Cons: May perform slower compared to `map+join` or `reduce` due to the overhead of function calls.
* **map+join**:
	+ Pros: More concise than `forEach`, and potentially faster due to the reduced number of function calls.
	+ Cons: Creates an intermediate string, which might be memory-intensive if the array is large.
* **reduce**:
	+ Pros: Can be faster due to the reduced overhead of function calls, but increases the risk of overflowing the accumulator.
	+ Cons: Might require more manual bookkeeping and handling edge cases.

**Libraries and Special Features**

There are no libraries mentioned in the benchmark. However, some special features of JavaScript are being used:

* The `forEach` method is an array method that executes a callback function for each element in the array.
* The `map` method transforms each element in the array into a new value.
* The `join` method concatenates all elements in an array into a single string, separated by a specified separator.
* The `reduce` method accumulates a value by executing a callback function for each element in the array.

**Alternatives**

Some alternative approaches to accumulating strings could be:

* Using a loop with a `for` statement instead of `forEach`, `map`, or `reduce`.
* Using `Array.prototype.reduce()` with an initial value instead of calling `reduce` as a method.
* Utilizing a library like Lodash, which provides a more concise and expressive way to perform string concatenation.

However, these alternatives are not being tested in this benchmark.

Related benchmarks:

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

Comparing performance of: forEach vs map+join vs reduce

Created: 5 years ago by: Registered User

Jump to the latest result

forEach

map+join

reduce

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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