Benchmark: Reduce vs Join in Javascript

Script Preparation code:

var digits = [];
for (var i=0; i<1000; i++) {
  digits[i] = ""+i+i;
}

Tests:

reduce
var result = digits.reduce((a, b) => a + b).trim();
join
var result = digits.join('').trim();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
join

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Android 10; Mobile; rv:131.0) Gecko/131.0 Firefox/131.0

Browser/OS: Firefox Mobile 131 on Android

View result in a separate tab

Test name	Executions per second
reduce	48775.9 Ops/sec
join	38199.1 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.

The benchmark is designed to compare two approaches: using the `reduce()` method and using the `join()` method in JavaScript. Both methods are used to concatenate an array of strings into a single string.

**Options being compared:**

1. **Reduce() Method:** This method applies a function to each element of an array, reducing it to a single value.
2. **Join() Method:** This method concatenates all elements of an array into a single string, using a specified separator (default is no separator).

**Pros and Cons of the approaches:**

1. `reduce()` Method:
	* Pros:
		+ Can be more flexible if you need to perform operations on each element before concatenation.
		+ Can reduce memory usage since it iterates over the array only once.
	* Cons:
		+ May be slower due to function invocation and iteration overhead.
2. `join()` Method:
	* Pros:
		+ Faster since it uses an optimized internal implementation for concatenating strings.
		+ More concise and readable code.

**Library usage:**

None of the test cases use any libraries explicitly. However, if we assume that the `Firefox/131` browser is using a custom JavaScript engine or has some specific optimizations enabled, there might be library-level differences that affect the benchmark results.

**Special JS features/syntax:**

There are no special JavaScript features or syntax mentioned in the provided code snippets. Both test cases use standard JavaScript and do not rely on any experimental or proposed features.

**Other alternatives:**

For this particular benchmark, other alternatives would involve:

1. Using `forEach()` method instead of `reduce()`, which might introduce additional function invocation overhead.
2. Using a custom loop implementation instead of `join()`, which could be slower due to the overhead of conditional statements and array indexing.
3. Adding more elements to the `digits` array, increasing the number of concatenations required by each approach.

Keep in mind that the choice of algorithm and implementation details can significantly impact performance, so it's essential to consider these factors when optimizing JavaScript code for specific use cases.

Related benchmarks:

Reduce vs Join in Javascript (version: 0)

Comparing performance of: reduce vs join

Created: 4 years ago by: Guest

Jump to the latest result

reduce

join

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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