Benchmark: large string comparison benchmark

Script Preparation code:

let s1MB = "0123456789".repeat(1000*100);
var strings1MB = Array.from(Array(20)).map(o=>s1MB + String.fromCharCode(32+~~(Math.random()*96)))

let s2MB = "0123456789".repeat(1000*200);
var strings2MB = Array.from(Array(20)).map(o=>s2MB + String.fromCharCode(32+~~(Math.random()*96)))

let s10MB = "0123456789".repeat(1000*1000);
var strings10MB = Array.from(Array(20)).map(o=>s10MB + String.fromCharCode(32+~~(Math.random()*96)))

let s10MB2 = "0123456789".repeat(1000*1000);
var strings10MB2 = Array.from(Array(20)).map(o=>s10MB + String.fromCharCode(32+~~(Math.random()*96)))

Tests:

1MB string comparison
const s1 = strings1MB[~~(strings1MB.length*Math.random())]; const s2 = strings1MB[~~(strings1MB.length*Math.random())]; const b = s1 === s2;
2MB string comparison
const s1 = strings2MB[~~(strings2MB.length*Math.random())]; const s2 = strings2MB[~~(strings2MB.length*Math.random())]; const b = s1 === s2;
10MB string comparison
const s1 = strings10MB[~~(strings10MB.length*Math.random())]; const s2 = strings10MB[~~(strings10MB.length*Math.random())]; const b = s1 === s2;
10MB string comparison (equal)
const s1 = strings10MB2[~~(strings10MB2.length*Math.random())]; const s2 = s1 + ""; const b = s1 === s2;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
1MB string comparison
2MB string comparison
10MB string comparison
10MB string comparison (equal)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript strings comparisons is crucial for optimizing and improving web applications.

**Benchmark Overview**

The benchmark tests the execution time of three different approaches for comparing large strings in JavaScript:

1. **Direct Comparison**: Directly comparing two strings using the `===` operator (`const b = s1 === s2;`).
2. **Hash-based Comparison**: Using a hash function (in this case, not explicitly stated) to compare two strings.
3. **Concatenation with Equality Check**: Concatenating a string with an empty string and then comparing it for equality (`const b = s1 === s2;`).

**Direct Comparison**

This approach is simple and straightforward but may be slow due to the following reasons:

*   It involves a full string comparison, which can be expensive in terms of CPU cycles.
*   The JavaScript engine needs to allocate memory for temporary variables during the comparison.

Pros: Easy to understand and implement, no additional dependencies required.

Cons: May be slower than other approaches due to the full string comparison.

**Hash-based Comparison**

This approach uses a hash function to reduce the complexity of the string comparison. However, in this benchmark, it's not explicitly stated what kind of hash function is used.

Pros:

*   Faster than direct comparison since it avoids a full string comparison.
*   Reduces memory allocation and deallocation during the comparison.

Cons: May not provide accurate results if the hash function is poorly implemented or doesn't cover all possible string cases. Also, some modern JavaScript engines might use optimized string comparisons that negate the benefits of this approach.

**Concatenation with Equality Check**

This approach concatenates a string with an empty string and then compares it for equality.

Pros: Can be faster than direct comparison since it involves fewer operations.
*   Uses less memory compared to direct comparison.

Cons:

*   May lead to unexpected behavior if not implemented correctly (e.g., the concatenated string might be garbage collected prematurely).
*   Requires an extra operation to concatenate and check for equality.

**Library Usage**

In this benchmark, no explicit libraries are used. However, some JavaScript engines like V8 (used by Chrome) have optimized string comparison algorithms that can affect the performance of these approaches.

**Special JS Feature or Syntax**

There is no special JS feature or syntax being tested in this benchmark.

**Other Alternatives**

Some alternative approaches for comparing strings could include:

*   Using `String.prototype.localeCompare()` method, which provides a locale-dependent string comparison.
*   Implementing a custom hash function and using it for string comparisons.
*   Using a library like Fast String Comparison or StringCompare to optimize the string comparison.

Keep in mind that these alternatives may not be relevant or applicable depending on your specific use case.

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/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
1MB string comparison	21673.3 Ops/sec
2MB string comparison	5327.3 Ops/sec
10MB string comparison	461.6 Ops/sec
10MB string comparison (equal)	3435385.2 Ops/sec

Related benchmarks:

large string comparison benchmark (version: 0)

Worst case large string comparison with large equal string comparison.

Comparing performance of: 1MB string comparison vs 2MB string comparison vs 10MB string comparison vs 10MB string comparison (equal)

Created: one year ago by: Guest

Jump to the latest result

1MB string comparison

2MB string comparison

10MB string comparison

10MB string comparison (equal)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):