Benchmark: Split vs Regex vs Replace Iteration

Script Preparation code:

var testString = new Array(1000).fill(0).map(() => Math.random().toFixed(4)).join("\n");

Tests:

Splitting
testString.split("\n").forEach(v => { const f = parseFloat(v); if (!window.screen) console.log(f); });
Regex
var regex = /([^\n]+)\n/g while (true) { const match = regex.exec(testString); if (!match) break; const f = parseFloat(match[1]); if (!window.screen) console.log(f); }
Replace
testString.replace(/[\-0-9.]/g, v => { const f = parseFloat(v); if (!window.screen) console.log(f); return ""; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Splitting
Regex
Replace

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/114.0.0.0 Safari/537.36

Browser/OS: Chrome 114 on Windows

View result in a separate tab

Test name	Executions per second
Splitting	1733.9 Ops/sec
Regex	1500.7 Ops/sec
Replace	310.8 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its options.

**Benchmark Purpose:**
The benchmark tests three different approaches to iterate over a large string:

1. Splitting
2. Using regular expressions (Regex)
3. Replacing characters in the string using a callback function

**Options Comparison:**

### Splitting

* **Pros:** Simple, efficient, and well-supported by most browsers.
* **Cons:** Can be slower for very large strings due to overhead of splitting the array.

### Regex

* **Pros:** Can handle complex string operations, fast for regular patterns.
* **Cons:** Can be slow for non-regular patterns or large strings due to the overhead of executing the regular expression engine.

### Replace

* **Pros:** Fast and efficient, suitable for large strings with many replacements.
* **Cons:** May not be as flexible as other options for handling complex string operations.

**Library Usage:**

The `forEach` method is used in the Splitting test case. This method is a built-in JavaScript function that iterates over an array (in this case, the result of `testString.split("\n")`) and executes a callback function on each element.

**Special JS Features/Syntax:**

* **Callback functions**: Used throughout the benchmark to perform operations on each string value. Callbacks are a fundamental concept in JavaScript for handling asynchronous or event-driven code.
* **Regular expressions (Regex)**: Used in the Regex test case. Regex is a powerful pattern-matching language that can be used for tasks like validating input data, parsing text, and more.

**Other Alternatives:**

For this specific benchmark, other alternatives could include:

* Using `Array.prototype.forEach.call()` instead of just `forEach` to ensure compatibility with older browsers.
* Using `while (testString.length > 0)` or a similar loop construct for the Splitting test case, as some browsers may not support `split()`.
* Using `String.prototype.replace()` without an argument array for the Replace test case, which might be slightly faster but has different implications for the code.

Keep in mind that these alternatives would likely change the performance characteristics of each approach and might require adjustments to the benchmarking script.

Related benchmarks:

Split vs Regex vs Replace Iteration (version: 0)

Comparing performance of: Splitting vs Regex vs Replace

Created: 3 years ago by: Guest

Jump to the latest result

Splitting

Regex

Replace

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):