Benchmark: Map vs Reduce for string

Script Preparation code:

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

Tests:

USING MAP and JOIN
const URLS = [ { "title": "USPS", "url": "https://tools.usps.com/go/TrackConfirmAction?tLabels=" }, { "title": "Parcels", "url": "https://parcelsapp.com/en/tracking/" }, { "title": "EVEREST", "url": "http://everest.forwardex.com/m/track.asp?track=" } ] URLS.map(url => `<a class="dropdown-item" href="${url.url + 'doc.tracking_number'}" target="_blank">${url.title}</a>`).join('');
USING REDUCE
const URLS = [ { "title": "USPS", "url": "https://tools.usps.com/go/TrackConfirmAction?tLabels=" }, { "title": "Parcels", "url": "https://parcelsapp.com/en/tracking/" }, { "title": "EVEREST", "url": "http://everest.forwardex.com/m/track.asp?track=" } ] const reduced_urls = URLS.reduce((acc, url) => { return acc + `<a class="dropdown-item" href="${url.url + 'doc.tracking_number'}" target="_blank">${url.title}</a>`; }, '');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
USING MAP and JOIN
USING REDUCE

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36

Browser/OS: Chrome 109 on Windows

View result in a separate tab

Test name	Executions per second
USING MAP and JOIN	3634042.8 Ops/sec
USING REDUCE	15451975.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The benchmark compares two approaches for transforming an array of objects into a string: using `Array.prototype.map()` and `Array.prototype.reduce()`. The test is designed to measure the performance difference between these two methods.

**Options Compared**

Two options are compared in this benchmark:

1. **Map**: Uses the `map()` method to create a new array with transformed elements, and then concatenates the resulting array into a single string using the `join()` method.
2. **Reduce**: Uses the `reduce()` method to accumulate the transformed elements into a single string.

**Pros and Cons of Each Approach**

*   **Map**:
    *   Pros:
        *   More readable and maintainable code
        *   Easier to understand and visualize the transformation process
    *   Cons:
        *   Requires creating an intermediate array, which can be memory-intensive for large datasets
        *   May not perform as well for very large datasets due to the overhead of creating and manipulating arrays
*   **Reduce**:
    *   Pros:
        *   More efficient in terms of memory usage, as it only accumulates a single string
        *   Can take advantage of optimization techniques like caching and loop unrolling
    *   Cons:
        *   Code can be less readable and more challenging to understand due to the accumulation process
        *   May require more complex logic for handling edge cases or errors

**Library and Special JS Features**

Neither the `map()` nor `reduce()` methods use any external libraries. However, they do utilize a few special JavaScript features:

*   **Arrow Functions**: The `map()` method uses arrow functions to define the transformation function.
*   **Template Literals**: The code uses template literals (backticks `` ` ``) to create string interpolations.

**Other Considerations**

When evaluating performance benchmarks like this one, consider factors such as:

*   **Dataset size**: The benchmark is designed for relatively small datasets (1000 elements). Larger datasets may favor the `reduce()` approach due to its more efficient memory usage.
*   **Hardware and software**: The measured performance is specific to the tested hardware and software configuration. Results may vary on different platforms or with different versions of JavaScript engines.

**Alternatives**

If you're looking for alternative approaches to transform arrays into strings, consider:

*   **forEach() + String.prototype.concat()**: Using `forEach()` to iterate over the array elements and concatenating them using `String.prototype.concat()`.
*   **Array.prototype.toString()**: Converting the entire array to a string using the `toString()` method.

Related benchmarks:

Map vs Reduce for string (version: 0)

Comparing performance of: USING MAP and JOIN vs USING REDUCE

Created: one year ago by: Guest

Jump to the latest result

USING MAP and JOIN

USING 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):