Benchmark: Reduce vs map/join

Script Preparation code:

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

Tests:

for
var result = ""; for (var i=0; i<strings.length; i++) { result = result+' x-'+strings[i]; }
reduce
var result = strings.reduce(function(string, i) { return string+' x-'+i; }, ""); result=result.substring(1);
map
var result = strings.map(function(i) { return 'x-'+i; }).join(' ');
for of
var result = ""; for (var i of strings) { result += ' x-'+i; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
reduce
map
for of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 25 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Safari/537.36

Browser/OS: Chrome 147 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
for	69586.1 Ops/sec
reduce	82432.1 Ops/sec
map	21393.1 Ops/sec
for of	55546.2 Ops/sec

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the details of this benchmark.

**Benchmark Definition**

The benchmark is called "Reduce vs map/join". It compares four different approaches to concatenating strings in JavaScript:

1. A traditional `for` loop
2. Using the `reduce()` method
3. Using the `map()` method and `join()` method
4. Using a modern `for...of` loop

**Test Cases**

Each test case has a small JavaScript snippet that performs the same task: concatenating strings in an array called `strings`. The snippets are as follows:

1. **"for"**: A traditional `for` loop that iterates over the `strings` array and concatenates each string to a result string using the `+=` operator.
```javascript
var result = "";
for (var i=0; i<strings.length; i++) {
    result = result + ' x-' + strings[i];
}
```
2. **"reduce"**: The `reduce()` method is used to concatenate each string in the array, accumulating the results in a single string.
```javascript
var result = strings.reduce(function(string, i) {
  return string + ' x-' + i;
}, "");
result = result.substring(1);
```
3. **"map"**: The `map()` method is used to create an array of new strings by prefixing each original string with "x-". Then, the `join()` method is used to concatenate these new strings into a single string.
```javascript
var result = strings.map(function(i) {
  return 'x-' + i;
}).join(' ');
```
4. **"for of"**: A modern `for...of` loop is used to iterate over the `strings` array and concatenate each string to a result string using the `+=` operator.
```javascript
var result = "";
for (var i of strings) {
    result += ' x-' + i;
}
```
**Library/Feature Used**

No external library or special JavaScript feature is used in these test cases.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **"for"**: Pros: straightforward, easy to understand; Cons: can be slow for large arrays.
2. **"reduce"**: Pros: efficient for concatenating strings; Cons: can be complex to understand if not familiar with the `reduce()` method.
3. **"map"**: Pros: flexible and expressive; Cons: may create unnecessary intermediate arrays, which can be memory-intensive.
4. **"for of"**: Pros: modern, concise syntax; Cons: less widely supported in older browsers.

**Other Alternatives**

Some other alternatives to these approaches are:

* Using a template string (e.g., `strings.join(' x-')`) if the output format is simple and known in advance.
* Using a library like Lodash or Underscore.js for more complex string manipulation tasks.
* Experimenting with different browser-specific features, such as WebAssembly or JavaScript modules.

Note that the results of this benchmark (91346.921875 executions per second for `reduce` on Chrome 129) suggest that using the `reduce()` method can be a good choice when concatenating strings in an array. However, it's essential to consider the specific requirements and constraints of your project before making a final decision.

Related benchmarks:

Reduce vs map/join (version: 0)

Comparing performance of: for vs reduce vs map vs for of

Created: 8 years ago by: Guest

Jump to the latest result

for

reduce

map

for of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):