Benchmark: str[i] before startsWith (6 cases)

Script Preparation code:

function get_data(){
  const res = "abc-def-ghi-\u26C6-jkl-mno"
  return res
}

Tests:

[MATCH] check str[i] before startsWith
const str = get_data() const res = str[12] === "\u26C6" && str.startsWith("abc-def-ghi-\u26C6")
[MATCH] startsWith immediatly
const str = get_data() const res = str.startsWith("abc-def-ghi-\u26C6")
[NOT MATCH] check str[i] before startsWith
const str = get_data() const res = str[14] === "\u26C6" && str.startsWith("abc-def-ghi-x-\u26C6")
[NOT MATCH] startsWith immediatly
const str = get_data() const res = str.startsWith("abc-def-ghi-x-\u26C6")
[NOT MATCH] check too far str[i] before startsWith
const str = get_data() const res = str[30] === "\u26C6" && str.startsWith("abc-def-ghi-\u26C6")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
[MATCH] check str[i] before startsWith
[MATCH] startsWith immediatly
[NOT MATCH] check str[i] before startsWith
[NOT MATCH] startsWith immediatly
[NOT MATCH] check too far str[i] before startsWith

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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Autogenerated LLM Summary (model llama3.2:3b, generated one year 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 measures the performance of string manipulation operations in different browsers.

**Test Cases**

There are four individual test cases:

1. `[MATCH] check str[i] before startsWith`
2. `[MATCH] startsWith immediatly`
3. `[NOT MATCH] check str[i] before startsWith`
4. `[NOT MATCH] startsWith immediatly`

These test cases cover different scenarios, including:

* Checking a specific index of the string (`str[12]`) before calling `startsWith` on the entire string.
* Calling `startsWith` immediately without checking a specific index first.
* Calling `startsWith` on a modified version of the string (with an extra character at the end) to test its efficiency.

**Library and Special JS Features**

The test case uses the built-in JavaScript `String` object, which is not a library. However, it does use Unicode characters (`\u26C6`) to create a non-ASCII string.

There are no special JavaScript features or syntax used in this benchmark.

**Approach Comparison**

The benchmark compares the performance of two approaches:

1. **Checking a specific index before calling `startsWith`**: This approach checks if the current character at a specific index (`str[12]`) is equal to a certain Unicode value (`\u26C6`). If it is, then `startsWith` can be called immediately.
2. **Calling `startsWith` immediately without checking a specific index first**: This approach calls `startsWith` on the entire string from the beginning.

**Pros and Cons of Each Approach**

1. **Checking a specific index before calling `startsWith`**:
	* Pros: Can reduce the number of iterations required for `startsWith`, as it allows the browser to stop searching once the condition is met.
	* Cons: May introduce additional overhead due to the extra check at the beginning.
2. **Calling `startsWith` immediately without checking a specific index first**:
	* Pros: Eliminates the need for an additional check, reducing overhead.
	* Cons: May require more iterations for `startsWith`, as it searches the entire string.

**Browser and Device Considerations**

The benchmark results are reported for Firefox 95 on desktop platforms. The performance variations between test cases may be influenced by differences in browser implementation, caching, or other factors that affect string manipulation operations.

**Other Alternatives**

If you're interested in exploring alternative approaches or libraries, consider the following:

1. **Using a different string library**: Depending on your requirements, you might want to experiment with other string libraries like `String.prototype.at()` (supported by some browsers) or third-party libraries.
2. **Implementing a custom string manipulation algorithm**: If you have specific performance requirements or need more control over the string processing workflow, consider implementing a custom algorithm tailored to your needs.

Keep in mind that benchmarking and optimizing JavaScript code can be complex due to the vast number of factors affecting performance. Always ensure that your optimizations are relevant and meaningful for your specific use case.

Related benchmarks:

str[i] before startsWith (6 cases) (version: 0)

Comparing performance of: [MATCH] check str[i] before startsWith vs [MATCH] startsWith immediatly vs [NOT MATCH] check str[i] before startsWith vs [NOT MATCH] startsWith immediatly vs [NOT MATCH] check too far str[i] before startsWith

Created: 4 years ago by: Guest

Jump to the latest result

[MATCH] check str[i] before startsWith

[MATCH] startsWith immediatly

[NOT MATCH] check str[i] before startsWith

[NOT MATCH] startsWith immediatly

[NOT MATCH] check too far str[i] before startsWith

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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