Benchmark: loop vs indexof - MeasureThat.net

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

let str = "";
for (let a = 0; a < 16384; a++) {
    str += "a";
}
str += "test";
for (let a = 0; a < 16384; a++) {
    str += "a";
}
let len=str.length;
let index=0;
let found=false;

Tests:

indeOf
let asd=str.indexOf("test");
loop
do{ if(str.charAt(index)=="t") { found=true; } index++; }while(index<len && found==false)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
indeOf
loop

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36 Edg/146.0.0.0

Browser/OS: Chrome 146 on Windows

View result in a separate tab

Test name	Executions per second
indeOf	94236664.0 Ops/sec
loop	9273784.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON compares two different approaches for finding a substring within a long string in JavaScript: using the `indexOf` method and using a manual loop with the `charAt` method.

### Options Compared:

1. **Using `indexOf`**:
   - **Benchmark Definition**: `let asd=str.indexOf("test");`
   - **Test Name**: `indeOf`
   - The `indexOf` method is a built-in JavaScript function that returns the index of the first occurrence of a specified value in a string. It is higher-level and designed specifically for substring searching.

2. **Using a Manual Loop**:
   - **Benchmark Definition**: 
     ```javascript
     do {
       if (str.charAt(index) == "t") {
         found = true;
       }
       index++;
     } while (index < len && found == false);
     ```
   - **Test Name**: `loop`
   - This method iteratively checks each character of the string using `charAt()`, which retrieves the character at a given index, until it finds the character 't'.

### Performance Results:
From the test results:
- The **loop** method achieved approximately `10,464,199` executions per second.
- The **indexOf** method achieved approximately `1,171,180` executions per second.

### Pros and Cons:

#### Using `indexOf`:
- **Pros**:
  - Simplicity: It is very straightforward and eliminates the need for boilerplate code.
  - Readability: The code is easier to understand, making maintenance easier.
  - Optimized Performance: Since it is a built-in method, it is often optimized by the JavaScript engine.
- **Cons**:
  - Slower performance in this particular benchmark, which may not be the case with different strings or in different scenarios.

#### Using a Manual Loop:
- **Pros**:
  - Potentially faster for this specific use case as evidenced by benchmark results.
  - Gives more control over the logic used to find substrings, allowing for modifications.
- **Cons**:
  - More verbose and requires more code, increasing the chance of errors.
  - Less readable and harder to maintain, particularly for those unfamiliar with the logic.

### Other Considerations:
- The performance of these methods may vary depending on the specific length of the string and the nature of the search. For example, if the substring occurs frequently, the `indexOf` method may outperform the loop since it terminates early upon finding the substring.
- Edge cases, such as searching for non-existent substrings or handling case sensitivity, can affect the results as well.

### Alternatives:
Other than these two approaches, there are additional options to consider for substring searching:
- **Regular Expressions**: Using `str.match(/test/)` or `str.search(/test/)` allows for flexible searching but may introduce overhead compared to the previous methods.
- **String.prototype.includes()**: This method can also be used for checking the presence of a substring in a more readable way (e.g., `str.includes("test")`), but it’s designed for boolean checks rather than finding indices.
- **Typed Arrays or Buffering**: For performance-critical applications, you may consider using lower-level techniques such as offloading searches to web workers or using typed arrays, though these methods are more complex.

This benchmark highlights the trade-off between readability and performance that developers often face when optimizing JavaScript code. It demonstrates the importance of understanding the tools available and selecting the right approach based upon the specific context of use.

Related benchmarks:

loop vs indexof (version: 1)

Comparing performance of: indeOf vs loop

Created: one year ago by: Guest

Jump to the latest result

indeOf

loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):